Display device

ABSTRACT

A display device includes a display panel including a display area on which a plurality of display elements is disposed and a non-display area on which one or more wires for driving the plurality of display elements are disposed. A back cover is attached to one surface of the display panel and has a plurality of openings. A roller unit winds or unwinds the back cover and the display panel, and a lifting unit moves the back cover and the display panel in a vertical direction. The plurality of openings overlaps the display panel, and each of the plurality of openings is disposed to be staggered with one or more of the openings in an adjacent row. A size of the back cover is larger than a size of the display panel.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit and priority of Korean PatentApplication No. 10-2018-0075054 filed on Jun. 28, 2018, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference as if fully set forth herein.

BACKGROUND 1. Technical Field

The present disclosure relates to a display device, and moreparticularly, to a rollable display device which is capable ofdisplaying images even in a rolled state.

2. Description of the Related Art

Display devices used for a monitor of a computer, a television, or acellular phone include an organic light emitting display device (OLED),which is a self-emitting device, and a liquid crystal display device(LCD), which requires a separate light source.

Display devices have a wide range of diverse applications, includingpersonal digital assistants, as well as monitors of computers andtelevisions. A display device with a large display area, and reducedvolume and weight is being studied.

Recently, a rollable display device manufactured by forming a displayunit and a wiring line on a flexible substrate has been receivingattention as a next generation display device. The flexible substratemay be a substrate made with a plastic material which is a flexiblematerial capable of displaying images even though the display device isrolled.

SUMMARY

An object of the present disclosure is to provide a display device whichincludes a back cover having high rigidity to protect and support adisplay panel.

Another object of the present disclosure is to provide a display devicewhich includes a back cover having high flexibility and capable of beingrolled together with a display panel.

Still another object of the present disclosure is to provide a displaydevice capable of relieving a stress generated when the display deviceis rolled, thereby minimizing or mitigating potential breakage of adisplay panel.

Still another object of the present disclosure is to provide a displaydevice capable of minimizing or reducing separation between a displaypanel and a back cover due to a stress generated when the display deviceis rolled.

Still another object of the present disclosure is to provide a displaydevice with enhanced adhesiveness between a display panel and a backcover.

Still another object of the present disclosure is to provide a displaydevice capable of minimizing or mitigating a potential problem ofbending between a display panel and a surface of a back cover generatedwhen the display panel and a back cover are fastened with a drivingunit.

Still another object of the present disclosure is to provide a displaydevice which reduces potential breakage of a driving IC by minimizingthe bending of the driving IC when the display device is rolled.

Still another object of the present disclosure is to provide a displaydevice with a side having enhanced rigidity to minimize or mitigatepotential breakage of a display device due to an external impact appliedto the side of the display device.

Still another object of the present disclosure is to provide a displaydevice which minimizes a risk of an injury of a user by preventing orminimizing a sharp edge of a back cover.

Still another object of the present disclosure is to provide a displaydevice with an improved reliability by minimizing permeation of moistureand oxygen into a display panel.

Still another object of the present disclosure is to provide a displaydevice which minimizes interference of a rear surface of a displaydevice by an edge of the display device when the display device isrolled.

Still another object to be achieved by the present disclosure is toprovide a display device which guides a display device so as not to bedeviated from a designed position when the display device is rolled.

Objects of the present disclosure are not limited to the specificobjects expressed above. Additional features, objects, and advantages ofthe disclosure, even if not expressed above, will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the disclosure. Theobjectives and other advantages of the disclosure may be be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present disclosure, as embodied and broadly described, a displaydevice includes: a display panel including a display area on which aplurality of display elements is disposed and a non-display area onwhich one or more wires for driving the plurality of display elementsare disposed; a back cover attached to one surface of the display paneland having a plurality of openings; a roller unit which winds or unwindsthe back cover and the display panel; and a lifting unit which moves theback cover and the display panel in a vertical direction, wherein theplurality of openings overlaps the display panel, each of the pluralityof openings is disposed to be staggered with one or more of the openingsin an adjacent row, a size of the back cover is larger than a size ofthe display panel, and each of a plurality of edges of the back covercorresponds to a respective one of a plurality of edges of the displaypanel and protrudes outside of the respective one of the plurality ofedges of the display panel.

According to another aspect of the present disclosure, a display deviceincludes: a display panel including a display area on which a pluralityof display elements is disposed and a non-display area on which one ormore wires for driving the plurality of display elements are disposed; aback cover supporting the display panel and having a plurality ofopenings; a housing unit configured to accommodate the display panel andthe back cover; a roller unit configured to wind or unwind the displaypanel and the back cover in a column direction; and a lifting unitconfigured to move the display panel and the back cover in or out of thehousing unit, wherein a width of the plurality of openings in the columndirection is smaller than a width of the plurality of openings in a rowdirection, a size of the back cover is larger than a size of the displaypanel, and each of a plurality of edges of the back cover corresponds toa respective one of a plurality of edges of the display panel andprotrudes outside of the respective one of the plurality of edges of thedisplay panel.

According to another aspect of the present disclosure, a rollabledisplay device includes: a flexible display panel including a displayarea on which a plurality of display elements is disposed and anon-display area on which one or more wires for driving the plurality ofdisplay elements are disposed; a back cover which is larger than theflexible display panel and is attached to one surface of the flexibledisplay panel; a roller unit which winds or unwinds the back cover andthe flexible display panel; and a lifting unit which moves the backcover and the display panel in a vertical direction, wherein the backcover includes a first support area, a second support area, and amalleable area disposed between the first support area and the secondsupport area and having a plurality of openings; the flexible displaypanel is disposed in the malleable area; and each of a plurality ofedges of the back cover protrudes outside of the non-display area of theflexible display panel.

Additional details and features of the exemplary embodiments areincluded in or may be learned from the detailed description and thedrawings.

According to an aspect of the present disclosure, a plurality ofopenings may be disposed in a back cover to provide a back cover havinga high flexibility.

According to another aspect the present disclosure, a plurality ofopenings may be selectively disposed in a portion of a back cover suchthat a back cover having both high rigidity and high flexibility may beprovided.

According to yet another aspect of the present disclosure, a stressgenerated when the display device is rolled may be relieved so as toprevent or mitigate potential breakage of the display panel.

According to still another aspect of the present disclosure, theadhesiveness between the display panel and the back cover may beimproved to prevent or minimize separation between the display panel andthe back cover when the display panel is rolled.

According to yet another aspect of the present disclosure, a flat stateof the display panel and the surface of the back cover without beingbent may be maintained.

According to still another aspect of the present disclosure, even withthe display panel wound around a roller, the driving IC may maintain aflat state to minimize breakage of the driving IC.

According to yet another aspect of the present disclosure, a sharp edgeof the back cover may be prevented or minimized to reduce risk ofinjury.

According to still another aspect of the present disclosure, therigidity at the side of the back cover may be increased to minimizedeformation of the back cover due to an external impact.

According to yet another aspect of the present disclosure, an edge of adisplay panel may be sealed to minimize moisture and oxygen permeatinginto the display panel, thereby improving the reliability of the displaypanel.

According to still another aspect of the present disclosure, the displaydevice may be guided while being rolled or unrolled without deviatingfrom a designed position.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory, and are intended to provide furtherexplanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosure andtogether with the description serve to explain the principles of thedisclosure. In the drawings:

FIGS. 1A and 1B are perspective views of a display device according toan exemplary embodiment of the present disclosure;

FIG. 2 is an exploded perspective view of a display device according toan exemplary embodiment of the present disclosure;

FIG. 3 is a schematic cross-sectional view for explaining a head bar anda display unit of a display device according to an exemplary embodimentof the present disclosure;

FIG. 4 is a cross-sectional view of a display device according to anexemplary embodiment of the present disclosure;

FIG. 5 is a plan view of a display unit of a display device according toan exemplary embodiment of the present disclosure;

FIG. 6 is a cross-sectional view taken along the line VI-VI′ of FIG. 5;

FIG. 7A is a plan view of a back cover of a display device according toan exemplary embodiment of the present disclosure;

FIG. 7B is an enlarged view of a region A of FIG. 7A.

FIG. 8A is a plan view of a display unit of a display device accordingto another exemplary embodiment of the present disclosure;

FIG. 8B is a plan view of a back cover of a display device according toanother exemplary embodiment of the present disclosure;

FIGS. 9A to 9C are cross-sectional views of a display device accordingto another exemplary embodiment of the present disclosure;

FIG. 10 is a schematic cross-sectional view for explaining a head barand a display unit of a display device according to another exemplaryembodiment of the present disclosure;

FIGS. 11A to 11C are plan views of back covers of a display deviceaccording to various exemplary embodiments of the present disclosure;

FIG. 12 is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure;

FIG. 13 is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure;

FIG. 14 is a schematic cross-sectional view for explaining a width of areinforcement area of a back cover of a display device according tostill another exemplary embodiment of the present disclosure;

FIG. 15A is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure;

FIG. 15B is a cross-sectional view taken along the line XVb-XVb′ of FIG.15A.

FIG. 16 is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure;

FIG. 17 is an enlarged cross-sectional view of a display unit of adisplay device according to still another exemplary embodiment of thepresent disclosure;

FIGS. 18 to 20 are enlarged cross-sectional views of a display unit of adisplay device according to various exemplary embodiments of the presentdisclosure;

FIG. 21 is a plan view of a display unit of a display device accordingto still another exemplary embodiment of the present disclosure;

FIG. 22 is a plan view of a display unit of a display device accordingto still another exemplary embodiment of the present disclosure;

FIG. 23 is a cross-sectional view of a display unit of FIG. 22 which iswound around a roller;

FIG. 24 is a plan view of a display unit of a display device accordingto still another exemplary embodiment of the present disclosure;

FIG. 25 is a cross-sectional view of a display unit of FIG. 24 which iswound around a roller; and

FIG. 26 is a plan view of a display unit of a display device accordingto still another exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings.

Advantages and features of the present disclosure, and implementationmethods thereof will be clarified through following example embodimentsdescribed with reference to the accompanying drawings. The presentdisclosure may, however, be embodied in different forms and should notbe construed as limited to the example embodiments set forth herein.Rather, these example embodiments are provided so that this disclosuremay be sufficiently thorough and complete to assist those skilled in theart to fully understand the scope of the present disclosure. Further,the present disclosure is only defined by scopes of claims.

A shape, a size, a ratio, an angle, and a number disclosed in thedrawings for describing embodiments of the present disclosure are merelyan example. Thus, the present disclosure is not limited to theillustrated details. Unless otherwise described, like reference numeralsrefer to like elements throughout. In the following description, whenthe detailed description of the relevant known function or configurationis determined to unnecessarily obscure an important point of the presentdisclosure, the detailed description of such known function orconfiguration may be omitted. In a case where terms “comprise,” “have,”and “include” described in the present specification are used, anotherpart may be added unless a more limiting term, such as “only,” is used.The terms of a singular form may include plural forms unless referred tothe contrary.

In construing an element, the element is construed as including an erroror tolerance range even where no explicit description of such an erroror tolerance range is provided.

In describing a position relationship, when a position relation betweentwo parts is described as, for example, “on,” “over,” “under,” or“next,” one or more other parts may be disposed between the two partsunless a more limiting term, such as “immediate(ly)” or “direct(ly),” isused. For example, when an element or layer is disposed “on” anotherelement or layer, a third layer or element may be interposedtherebetween.

Although the terms “first,” “second,” and the like may be used herein todescribe various elements, these elements should not be limited by theseterms as they are not used to define a particular order. These terms areused only to distinguish one element from another. For example, a firstelement could be termed a second element, and, similarly, a secondelement could be termed a first element, without departing from thescope of the present disclosure.

A size and a thickness of each component illustrated in the drawings areillustrated for convenience of description, and the present disclosureis not limited to the size and the thickness of the componentillustrated, unless otherwise stated.

Features of various embodiments of the present disclosure may bepartially or overall coupled to or combined with each other, and may bevariously inter-operated with each other and driven technically, asthose skilled in the art can sufficiently understand. Embodiments of thepresent disclosure may be carried out independently from each other, ormay be carried out in association with each other.

Hereinafter, a display device according to exemplary embodiments of thepresent disclosure will be described in detail with reference toaccompanying drawings.

<Display Device—Rollable Display Device>

A rollable display device may also be referred to as a display devicecapable of displaying images even though it is rolled. The rollabledisplay device may have a higher flexibility as compared with a generaldisplay device of the related art. Depending on whether the rollabledisplay device is in use, a shape of the rollable display device may befreely varied. Specifically, when the rollable display device is not inuse, the rollable display device may be rolled to be stored with areduced volume. On the other hand, when the rollable display device isin use, the rolled rollable display device may be unrolled to be used,e.g., to display images.

FIGS. 1A and 1B are perspective views of a display device according toan exemplary embodiment of the present disclosure. As shown in FIGS. 1Aand 1B, a display device 100 according to an exemplary embodiment of thepresent disclosure includes a display unit DP and a housing unit HP.

The display unit DP is a structure for displaying images to a user. Forexample, the display unit DP may include a display element and acircuit, a wiring line, and a component for driving the display element.In this case, since the display device 100 according to an exemplaryembodiment of the present disclosure is a rollable display device 100,the display unit DP may be configured to be wound and unwound. Forexample, the display unit DP may include a display panel and a backcover each having a flexibility to be wound or unwound. The display unitDP will be described below in more detail with reference to FIGS. 5 to7B.

The housing unit HP is a case in which the display unit DP may beaccommodated. The display unit DP may be wound to be accommodated in thehousing unit HP, for example, as shown in FIG. 1B. The display unit DPmay be unwound to be disposed outside the housing unit HP, for example,as shown in FIG. 1A.

The housing unit HP may have an opening HPO to allow the display unit DPto be wound into the housing unit HP and to be unwound out of thehousing unit HP. The display unit DP may move through the opening HPO ofthe housing unit HP in a vertical direction.

The display unit DP of the display device 100 may be switched from afully unwound state to a fully wound state or from a fully wound stateto a fully unwound state.

FIG. 1A illustrates the display unit DP of the display device 100 in thefully unwound state. In the fully unwound state, the display unit DP ofthe display device 100 is disposed outside of the housing unit HP. Thatis, in order for a user to view images on the display device 100, thedisplay unit DP may be unwound to be disposed outside of the housingunit HP as much as possible. When the display unit DP cannot be furtherunwound, it may be defined as a fully unwound state.

FIG. 1B illustrates the display unit DP of the display device 100 in thefully wound state. In the fully wound state, the display unit DP of thedisplay device 100 is accommodated in the housing unit HP and cannot befurther wound. That is, when the user is not watching the images throughthe display device 100, it may be more advantageous from the viewpointof an outer appearance that the display unit DP is not disposed outsideof the housing unit HP. Therefore, when the display unit DP is wound tobe accommodated in the housing unit HP, it may be defined as a fullywound state. Further, when the display unit DP is in a fully wound stateto be accommodated in the housing unit HP, the volume of the displaydevice 100 is reduced and the display device 100 may be more easilycarried.

In order to switch the display unit DP between a fully unwound state anda fully wound state, a driving unit is provided to wind or unwind thedisplay unit DP.

<Driving Unit>

FIG. 2 is an exploded perspective view of a display device according toan exemplary embodiment of the present disclosure. FIG. 3 is a schematiccross-sectional view for explaining a head bar 164 and a display unit DPof a display device according to an exemplary embodiment of the presentdisclosure. FIG. 4 is a cross-sectional view of a display deviceaccording to an exemplary embodiment of the present disclosure. FIG. 4is a schematic cross-sectional view for explaining a roller 151 and adisplay unit DP of a display device 100 according to an exemplaryembodiment of the present disclosure. For the convenience ofdescription, FIG. 3 illustrates only a head bar 164 and a display unitDP, and FIG. 4 illustrates only a housing unit HP, a roller 151, and adisplay unit DP.

First, as illustrated in FIG. 2, a driving unit MP includes a rollerunit 150 and a lifting unit 160.

A roller unit 150 may wind or unwind the display unit DP connected tothe roller unit 150 while rotating in a first direction DR1 or a seconddirection DR2. The roller unit 150 may include a roller 151, a rollersupport unit 152, and a roller rotating unit 153.

The roller 151 is a member around which the display unit DP may bewound. The roller 151 may, for example, have a cylindrical shape. Alower edge of the display unit DP may be fixed to the roller 151. Whenthe roller 151 rotates, the display unit DP fixed to the roller 151through the lower edge may be wound around the roller 151. On the otherhand, when the roller 151 rotates in an opposite direction, the displayunit DP which is wound around the roller 151 may be unwound from theroller 151.

The roller support units 152 may support the roller 151 at both sides ofthe roller 151. Specifically, the roller support units 152 may bedisposed on a bottom plate HPF of the housing unit HP. Upper sides ofthe roller support units 152 may be coupled to both ends of the roller151, respectively. Therefore, the roller support units 152 may supportthe roller 151 to be spaced apart from the bottom plate HPF of thehousing unit HP. In this case, the roller 151 may be rotatably coupledto the roller support units 152.

The roller rotating units 153 may rotate the roller 151 in the firstdirection DR1 or the second direction DR2. The roller rotating units 153may be disposed in a pair of roller support units 152, respectively. Forexample, the roller rotating units 153 may be rotary motors whichtransmit a torque to the roller 151, but are not limited thereto.

The lifting unit 160 may move the display unit DP in a verticaldirection in accordance with the driving of the roller unit 150. Thelifting unit 160 may include a link support unit 161, a link unit 162, alink lifting unit 163, and a head bar 164.

The link support unit 161 may support the link unit 162 and the linklifting unit 163. Specifically, the link support unit 161 may supportthe link unit 162 and the display unit DP which may move in the verticaldirection so as not to collide with a boundary of the opening HPO of thehousing unit HP. The link support unit 161 may support the link unit 162and the display unit DP to move only in a vertical direction withoutmoving in forward and backward directions.

The link unit 162 may include a plurality of links 162L hinged with eachother. The plurality of links 162L may be rotatably hinged to each otherto be moved in the vertical direction by the link lifting unit 163. Whenthe link unit 162 moves in the vertical direction, the plurality oflinks 162L may rotate to be farther away from each other or closer toeach other. Detailed description thereof will be made with reference toFIG. 4.

The link lifting unit 163 may move the link unit 162 in the verticaldirection. The link lifting unit 163 may rotate the plurality of links162L of the link unit 162 to be closer to each other or rotate theplurality of links 162L to be farther away from each other. The linklifting unit 163 may lift or lower the link unit 162 to lift or lowerthe display unit DP connected to the link unit 162.

In this case, the link lifting unit 163 may be driven in synchronizationwith the roller rotating unit 153 so that the roller unit 150 and thelifting unit 160 may simultaneously operate. For example, when thedisplay unit DP is to be switched from a fully unwound state to a fullywound state, the roller unit 150 may operate to wind the display unit DParound the roller 151. Simultaneously with this, the lifting unit 160may operate to rotate the plurality of links 162L of the link unit 162to lower the display unit DP. Further, when the display unit DP is to beswitched from a fully wound state to a fully unwound state, the rollerunit 150 may operate to unwind the display unit DP from the roller 151.Simultaneously with this, the lifting unit 160 may operate to rotate theplurality of links 162L of the link unit 162 to lift the display unitDP.

The head bar 164 of the lifting unit 160 may be fixed to an uppermostend of the display unit DP. The head bar 164 may be coupled to the linkunit 162 to move the display unit DP in the vertical direction inaccordance with the rotation of the plurality of links 162L of the linkunit 162. That is, the display unit DP may move in the verticaldirection by the link unit 162 coupled to the head bar 164 and the linklifting unit 163.

As illustrated in FIG. 3, the head bar 164 may be disposed at theuppermost end of the display unit DP so as to cover a portion of a frontsurface and a portion of a rear surface of the display unit DP.

The head bar 164 may include a first head bar 164 a and a second headbar 164 b. The first head bar 164 a may cover a portion of the frontsurface of the display unit DP. The first head bar 164 a may cover onlya part of the front surface adjacent to an uppermost edge of the displayunit DP so as not to cover an image displayed on the front surface ofthe display unit DP.

The second head bar 164 b may cover a portion of the rear surface of thedisplay unit DP. The second head bar 164 b may cover a part of the rearsurface adjacent to the uppermost edge of the display unit DP. However,where no image is displayed on the rear surface of the display unit DP,the second head bar 164 b may overlap a larger portion of the displayunit DP than the first head bar 164 a.

In order to fasten the display unit DP with the first head bar 164 a andthe second head bar 164 b, a first fastening hole AH1 may be formed inthe display unit DP. A screw SC may penetrate the first fastening holeAH1 to fasten the first head bar 164 a, the display unit DP, and thesecond head bar 164 b together.

Pem nuts PN may be disposed in the second head bar 164 b and beconnected to the link unit 162 of the lifting unit 160. The second headbar 164 b and the link unit 162 of the lifting unit 160 may be fastenedwith each other by the pem nuts PN. Therefore, when the link unit 162 ofthe lifting unit 160 moves in the vertical direction, the second headbar 164 b fastened with the link unit 162, and the first head bar 164 aand the display unit DP fastened with the second head bar 164 b may movetogether in the vertical direction.

Even though the first head bar 164 a and the second head bar 164 b areillustrated in FIG. 2 to have a linear shape, the shapes of the firsthead bar 164 a and the second head bar 164 b are not limited there toand may be changed in various forms.

Hereinafter, a driving operation of the driving unit MP will bedescribed in detail with reference to FIG. 4.

As shown in FIG. 4, a lower edge of the display unit DP may be coupledto the roller 151. When the roller 151 is rotated in the first directionDR1, that is, a clockwise direction, by the roller rotating unit 153(FIG. 2), the display unit DP may be wound around the roller 151 so thata rear surface of the display unit DP is in close contact with a surfaceof the roller 151.

On the other hand, when the roller 151 is rotated in the seconddirection DR2, that is, a counter clockwise direction, by the rollerrotating unit 153, the display unit DP wound around the roller 151 maybe unwound from the roller 151 to be disposed outside of the housingunit HP.

In some exemplary embodiments, the display device 100 may include adriving unit MP having a different structure than the above-describeddriving unit MP. That is, as long as the display unit DP can be woundand unwound, the above-described configuration of the roller unit 150and the lifting unit 160 may be modified, some elements may be omitted,or other elements may be added.

<Display Unit>

FIG. 5 is a plan view of a display unit DP of a display device accordingto an exemplary embodiment of the present disclosure. FIG. 6 is across-sectional view taken along the line VI-VI′ of FIG. 5.

As illustrated in FIG. 5, the display unit DP may include a back cover110, a display panel 120, a flexible film 130, and a printed circuitboard 140.

The display panel 120 is a panel for displaying images, for example, toa user. The display panel 120 may include a display element to displayimages, a driving element to drive the display element, and wiring linesto transmit various signals to the display element and the drivingelement. The display element may be defined in different ways dependingon a type of the display panel 120. For example, if the display panel120 is an organic light emitting display panel, the display element maybe an organic light emitting diode which includes an anode, an organiclight emitting layer, and a cathode. For example, if the display panel120 is a liquid crystal display panel, the display element may be aliquid crystal display element. Hereinafter, even though the displaypanel 120 may be described as an organic light emitting display panel asan example, the display panel 120 is not limited to the organic lightemitting display panel. Further, since the display device 100 accordingto an exemplary embodiment of the present disclosure is a rollabledisplay device, the display panel 120 may be implemented as a flexibledisplay panel to be wound around or unwound from the roller 151.

The display panel 120 may include a display area AA and a non-displayarea NA.

The display area AA is an area where images may be displayed in thedisplay panel 120. In the display area AA, a plurality of sub pixels anda circuit for driving the plurality of sub pixels may be disposed. Theplurality of sub pixels represent minimum units which configure thedisplay area AA, and a display element may be disposed in each of theplurality of sub pixels. For example, an organic light emitting diodeincluding an anode, an organic light emitting layer, and a cathode maybe disposed in each of the plurality of sub pixels, but it is notlimited thereto. Further, a circuit for driving the plurality of subpixels may include a driving element and a wiring line. For example, thecircuit may be formed of a thin film transistor, a storage capacitor, agate line, and a data line, but is not limited thereto.

The non-display area NA of the display panel 120 is an area where noimage can be displayed. In the non-display area NA, various wiring linesand circuits for driving the organic light emitting diode of the displayarea AA may be disposed. For example, in the non-display area NA, a linkline to transmit signals to the plurality of sub pixels and circuits ofthe display area AA, or a driving IC such as a gate driver IC or a datadriver IC may be disposed, but the non-display area is not limitedthereto.

The flexible film 130 may be a film in which various components aredisposed on a base film having a malleability. The flexible film 130 maysupply a signal to the plurality of sub pixels and the circuits of thedisplay area AA, and may be electrically connected to the display panel120. The flexible film 130 may be disposed at one end of the non-displayarea NA of the display panel 120 to supply a power voltage or a datavoltage to the plurality of sub pixels and the circuits of the displayarea AA. Even though four flexible films 130 are illustrated in FIG. 5as an example, the number of flexible films 130 may vary depending onthe design and is not limited to the illustrated example.

A driving IC, such as a gate driver IC or a data driver IC, may bedisposed on the flexible film 130. The driving IC may be a component toprocess data for displaying images and a driving signal for processingthe data. The driving IC may be disposed by a chip on glass (COG), achip on film (COF), or a tape carrier package (TCP) technique dependingon a mounting method. However, for the convenience of description, thedriving IC may be described, for example, as being mounted on theflexible film 130 by a chip on film technique, but is not limitedthereto.

The printed circuit board 140 may be disposed at one end of the flexiblefilm 130 to be connected to the flexible film 130. The printed circuitboard 140 may be a component to supply signals to the driving IC. Theprinted circuit board 140 may supply various signals, such as a drivingsignal or a data signal, to the driving IC. Various components may bedisposed on the printed circuit board 140. For example, a timingcontroller or a power source unit may be disposed on the printed circuitboard 140. In the meantime, even though one printed circuit board 140 isillustrated in FIG. 5 as an example, the number of printed circuitboards 140 may vary depending on the design and is not limited thereto.

The back cover 110 may be disposed on rear surfaces of the display panel120, the flexible film 130, and the printed circuit board 140 to supportthe display panel 120, the flexible film 130, and the printed circuitboard 140. Therefore, a size of the back cover 110 may be larger than asize of the display panel 120. The back cover 110 may protect othercomponents of the display unit DP from any external impact. Even thoughthe back cover 110 may be formed of a material having a rigidity, atleast a part of the back cover 110 may have a flexibility to be wound orunwound together with the display panel 120. For example, the back cover110 may be formed of a metal material, such as steel use stainless (SUS)or invar, or a plastic material. However, if the material of the backcover 110 satisfies physical conditions such as a thermal strain amount,a radius of curvature, and rigidity, the material may be diverselychanged, and is not limited thereto.

As shown in FIG. 6, the display panel 120 may include a substrate 121, abuffer layer 122, a pixel unit 123, an encapsulation layer 124, and anencapsulation substrate 125.

The substrate 121, which is a base member for supporting variouscomponents of the display panel 120, may be formed of an insulatingmaterial. The substrate 121 may be formed of a material having aflexibility to allow the display panel 120 to be wound or unwound and,for example, may be formed of a plastic material such as polyimide PI.

The buffer layer 122 may suppress moisture and/or oxygen permeating fromthe outside of the substrate 121 from being diffused. The buffer layer122 may be formed of a single layer or a double layer of silicon oxideSiOx and silicon nitride SiNx, but is not limited thereto.

The pixel unit 123 may include a plurality of organic light emittingdiodes and a circuit for driving the plurality of organic light emittingdiodes. The pixel unit 123 may be in an area corresponding to thedisplay area AA. The organic light emitting diode may include an anode,an organic light emitting layer, and a cathode.

The anode may supply holes to the organic light emitting layer and beformed of a conductive material having a high work function. Forexample, the anode may be formed of tin oxide (TO), indium tin oxide(ITO), indium zinc oxide (IZO), or indium zinc tin oxide (ITZO), but isnot limited thereto.

The organic light emitting layer may be supplied with holes from theanode and supplied with electrons from the cathode to emit light. Theorganic light emitting layer may be formed of a red organic lightemitting layer, a green organic light emitting layer, a blue organiclight emitting layer, or a white organic light emitting layer dependingon a color of light emitted from the organic light emitting layer. Inthis case, if the organic light emitting layer is a white organic lightemitting layer, color filters having various colors may be additionallydisposed.

The cathode may supply electrons to the organic light emitting layer andbe formed of a conductive material having a low work function. Forexample, the cathode may be formed of any one or more selected from agroup of metals, such as magnesium (Mg), silver (Ag), and aluminum (Al),and any alloy thereof, but is not limited thereto.

The display panel 120 may be a top emission type or a bottom emissiontype, depending on an emission direction of light emitted from theorganic light emitting diode.

For the top emission type, light emitted from the organic light emittingdiode may be emitted toward an upper portion of the substrate 121 onwhich the organic light emitting diode is formed. In the case of the topemission type, a reflective layer may be formed below the anode to allowthe light emitted from the organic light emitting diode to travel to theupper portion of the substrate 121, that is, toward the cathode.

For the the bottom emission type, light emitted from the organic lightemitting diode may be emitted toward a lower portion of the substrate121 on which the organic light emitting diode is formed. In the case ofthe bottom emission type, the anode may be formed only of a transparentconductive material to allow the light emitted from the organic lightemitting diode to travel toward the lower portion of the substrate 121,and the cathode may be formed of the metal material having a highreflectivity.

Hereinafter, for the convenience of description, the display device 100according to an exemplary embodiment of the present disclosure may bedescribed, for example, as a bottom emission type display device, but itis not limited thereto.

A circuit for driving the organic light emitting diode may be disposedin the pixel unit 123. The circuit may be formed of a thin filmtransistor, a storage capacitor, a gate line, a data line, and a powerline, but the circuit may take various other forms depending on thedesign of the display device 100.

The encapsulation layer 124 may be disposed on the pixel unit 123 andcover the pixel unit 123. The encapsulation layer 124 may closely sealthe organic light emitting diode of the pixel unit 123. Theencapsulation layer 124 may protect the organic light emitting diode ofthe pixel unit 123 from external moisture, oxygen, and impacts. Theencapsulation layer 124 may be formed by alternately laminating aplurality of inorganic layers and a plurality of organic layers. Forexample, the inorganic layer may be formed of an inorganic material,such as silicon nitride SiNx, silicon oxide SiOx, and aluminum oxideAlOx, and the organic layer may be formed of epoxy or acrylic polymer,but they are not limited thereto.

The encapsulation substrate 125 may be disposed on the encapsulationlayer 124. The encapsulation substrate 125 may protect the organic lightemitting diode of the pixel unit 123 together with the encapsulationlayer 124. The encapsulation substrate 125 may protect the organic lightemitting diode of the pixel unit 123 from external moisture, oxygen, andimpacts. The encapsulation substrate 125 may be formed of a metalmaterial, which has a high corrosion resistance and can be easilyprocessed in the form of foil or thin film, such as aluminum (Al),nickel (Ni), chromium (Cr), and an alloy material of iron (Fe) andnickel. Therefore, if the encapsulation substrate 125 is formed of ametal material, the encapsulation substrate 125 may be implemented as anultra-thin film and have a high resistance against external impacts andscratches.

A first adhesive layer AD1 may be disposed between the encapsulationlayer 124 and the encapsulation substrate 125. The first adhesive layerAD1 may bond the encapsulation layer 124 and the encapsulation substrate125 to each other. The first adhesive layer AD1 may be formed of amaterial having an adhesiveness and may be a thermosetting or naturalcuring adhesive. For example, the first adhesive layer AD1 may be formedof an optical clear adhesive (OCA) or a pressure sensitive adhesive(PSA), but is not limited thereto.

The first adhesive layer AD1 may be provided to enclose theencapsulation layer 124 and the pixel unit 123. That is, the pixel unit123 may be sealed by the buffer layer 122 and the encapsulation layer124, and the encapsulation layer 124 and the pixel unit 123 may besealed by the buffer layer 122 and the first adhesive layer AD1.Together with the encapsulation layer 124 and the encapsulationsubstrate 125, the first adhesive layer AD1 may protect the organiclight emitting diode of the pixel unit 123 from external moisture,oxygen, and impacts. In this case, the first adhesive layer AD1 mayfurther include an absorbent. The absorbent may be particles havinghygroscopicity and absorb external moisture and oxygen to minimizepermeation of the moisture and oxygen into the pixel unit 123.

The back cover 110 may be disposed on the encapsulation substrate 125.The back cover 110 may be disposed to be in contact with theencapsulation substrate 125 of the display panel 120 to protect thedisplay panel 120. In order to protect the display panel 120, the backcover 110 may be formed of a rigid metal or plastic material.

The back cover 110 may include a plurality of openings 111. Theplurality of openings 111 may allow the back cover 110 to haveflexibility. The plurality of openings 111 may be flexibly deformed andallow the back cover 110 to be wound around the roller 151 or unwoundfrom the roller 151 together with the display panel 120. Detaileddescription thereof will be provided below with reference to FIGS. 7Aand 7B.

A second adhesive layer AD2 may be disposed between the encapsulationsubstrate 125 and the back cover 110. The second adhesive layer AD2 maybond the encapsulation substrate 125 and the back cover 110 to eachother. The second adhesive layer AD2 may be formed of a material havingan adhesiveness and may be a thermosetting or natural curing adhesive.For example, the second adhesive layer AD2 may be formed of an opticalclear adhesive (OCA) or a pressure sensitive adhesive (PSA), but is notlimited thereto.

Even though the plurality of openings 111 of the back cover 110 isillustrated in FIG. 6 as not being filled with the second adhesive layerAD2, some or all of the plurality of openings 111 may be filled with thesecond adhesive layer AD2. If the plurality of openings 111 of the backcover 110 is filled with the second adhesive layer AD2, a contact areabetween the second adhesive layer AD2 and the back cover 110 isincreased so as to prevent or mitigate a separation phenomenon.

Even though not illustrated in FIG. 6, a translucent film may be furtherdisposed on an outer surface of the substrate 121 (i.e., a lower surfaceof the substrate 121 as shown in FIG. 6). The translucent film mayperform a function of protecting a front surface or a viewing surface ofthe display panel 120 or minimizing the reflection of external lightincident onto the display panel 120. For example, the translucent filmmay be at least one of a polyethyleneterephthalate (PET) film, ananti-reflection film, a polarizer film, and a transmittance controllablefilm, but is not limited thereto.

Hereinafter, the back cover 110 will be described in more detail withreference to FIGS. 7A and 7B.

<Detailed Configuration of an Example Back Cover>

FIG. 7A is a plan view of a back cover of a display device according toan exemplary embodiment of the present disclosure. FIG. 7B is anenlarged view of a region A of FIG. 7A.

As illustrated in FIG. 7A, the back cover 110 may include a support areaPA and a malleable area MA. More specifically, the back cover 110 mayinclude a first support area PA1 of an uppermost end of the back cover110, a second support area PA2 of a lowermost end of the back cover 110,and the malleable area MA between the first support area PA1 and thesecond support area PA2.

The first support area PA1 of the back cover 110 may be an uppermostarea of the back cover 110 and may be fastened with the head bar 164.The first support area PA1 may include first fastening holes AH1 to befastened with the head bar 164. As described in detail with reference toFIG. 3, screws SC may be provided to pass through the head bar 164 andthe first fastening holes AH1 to fasten the head bar 164 with the firstsupport area PA1 of the back cover 110. If the first support area PA1 isfastened with the head bar 164, when the link unit 162 fastened with thehead bar 164 is lifted or lowered, the back cover 110 may also be liftedand lowered together with the display panel 120 attached to the backcover 110. Even though FIG. 7 illustrates, for example, five firstfastening holes AH1, the number of first fastening holes AH1 is notlimited thereto. Further, even though the back cover 110 is illustratedin FIG. 7A as being fastened with the head bar 164 using the firstfastening holes AH1, it is not limited thereto. The back cover 110 andthe head bar 164 may be fastened with each other without using aseparate fastening hole.

The second support area PA2 of the back cover 110 may be a lowermostarea of the back cover 110 and may be fastened with the roller 151. Thesecond support area PA2 may include second fastening holes AH2 to befastened with the roller 151. For example, screws SC may be provided topass through the roller 151 and the second fastening holes AH2 to fastenthe roller 151 and the second support area PA2 of the back cover 110with each other. If the second support area PA2 is fastened with theroller 151, the back cover 110 may be wound around or unwound from theroller 151 by the rotation of the roller 151. Even though FIG. 7Aillustrates, for example, two second fastening holes AH2, the number ofsecond fastening holes AH2 is not limited thereto.

The malleable area MA of the back cover 110 may be an area which iswound around or unwound from the roller 151 together with the displaypanel 120. The malleable area MA may overlap at least the display panel120 among other components of the display unit DP.

A plurality of openings 111 may be disposed in the malleable area MA ofthe back cover 110. When the display unit DP is wound or unwound, theplurality of openings 111 may be deformed by a stress applied to thedisplay unit DP. Specifically, when the display unit DP is wound orunwound, the malleable area MA of the back cover 110 may be deformed asthe plurality of openings 111 contracts or expands. Further, as theplurality of openings 111 contracts or expands, a slip phenomenon of thedisplay panel 120 disposed on the malleable area MA of the back cover110 may be minimized so that the stress applied to the display panel 120may be minimized.

When the display panel 120 and the back cover 110 are wound, adifference between a length of the display panel 120 wound around theroller 151 and a length of the back cover 110 wound around the roller151 may be caused due to the difference in respective radii of curvatureof the display panel 120 and the back cover 110. For example, when theback cover 110 and the display panel 120 are wound around the roller151, a length of the back cover 110 required for being wound around theroller 151 once may be different from a length of the display panel 120required for being wound around the roller 151 once. That is, since thedisplay panel 120 is disposed outside the back cover 110 with respect tothe roller 151, a length of the display panel 120 required to be woundaround the roller 151 once may be larger than a length of the back cover110 required to be wound around the roller 151 once. As described above,the winding lengths of the back cover 110 and the display panel 120 maybe different from each other due to the difference in respective radiiof curvature at the time of winding the display unit DP, and the displaypanel 120 attached to the back cover 110 may slide to move from itsoriginal position. In this case, a phenomenon that the display panel 120slides from the back cover 110 due to the stress and the difference inradii of curvature caused by the winding may be defined as a slipphenomenon. When the slip phenomenon is excessively increased, thedisplay panel 120 may be detached from the back cover 110, or failuressuch as cracks may be caused.

In this case, in the display device 100 according to an exemplaryembodiment of the present disclosure, even when the display unit DP iswound or unwound and a stress is applied to the display unit DP, theplurality of openings 111 of the back cover 110 may be flexibly deformedto relieve the stress applied to the back cover 110 and the displaypanel 120. For example, when the back cover 110 and the display panel120 are wound around the roller 151, a stress which deforms the backcover 110 and the display panel 120 in a vertical direction may beapplied. In this case, the plurality of openings 111 of the back cover110 may extend in a vertical direction of the back cover 110, and thelength of the back cover 110 may be flexibly deformed. Therefore, thedifference in the respective lengths of the back cover 110 and thedisplay panel 120 caused by the difference in respective radii ofcurvature during the process of winding the back cover 110 and thedisplay panel 120 may be compensated by the plurality of openings 111 ofthe back cover 110. Further, the plurality of openings 111 may bedeformed during the process of winding the back cover 110 and thedisplay panel 120 so that a stress which is applied to the display panel120 from the back cover 110 may also be relieved.

As shown in FIGS. 7A and 7B, the plurality of openings 111 may bestaggered from a plurality of openings 111 in adjacent rows. Forexample, a plurality of openings 111 disposed in one row may bestaggered from a plurality of openings 111 disposed in a row adjacent tothe one row. Specifically, respective centers of the plurality ofopenings 111 disposed in an odd-numbered row may be staggered fromrespective centers of the plurality of openings 111 disposed in aneven-numbered row. For example, the respective centers of the pluralityof openings 111 disposed in an odd-numbered row may be staggered by ahalf of width 111WR of the openings 11 in a row direction from therespective center of the plurality of openings 111 disposed in aneven-numbered row. However, the arrangement of the plurality of openings111 illustrated in FIG. 7A is just an example, and is not limitedthereto.

Due to the openings 111 being staggered, a distance 111WB (see, e.g.,FIG. 7B) between two adjacent openings 111 with their centers aligned ina column direction may be minimized. Specifically, an area between theopenings 111 with their centers aligned in a column direction in themalleable area MA may have a relatively high rigidity. When the backcover 110 is wound, the back cover 110 is to be bent in a columndirection. Therefore, as the distance 111WB between two adjacentopenings 111 with their centers aligned in the column is increased, itmay be harder to bend the back cover 110 in the column direction. Inthis case, since the openings 111 are staggered from row to row, thedistance 111WB between two adjacent openings 111 with their centersaligned in the column direction may be minimized or reduced, and thearea between the openings 111 may also be minimized or reduced, ascompared to a configuration in which the openings are not staggered.Accordingly, the distance 111WB between two adjacent openings 111 withtheir centers aligned in the column direction may be reduced, and themalleable area MA may be filled with more openings 111 in the columndirection to remove or reduce an area without openings 111. Therefore,because the distance 111WB of the rigid area between the plurality ofopenings 111 in the column direction is minimized or reduced, theoverall rigidity of the back cover 110 may be enhanced withoutinterfering the winding or unwinding of the back cover 110.

As shown in FIG. 7B, a maximum width 111WR of the plurality of openings111 in the row direction may be larger than a maximum width 111WC in thecolumn direction. That is, as illustrated in FIG. 7B, the maximum width111WR of the plurality of openings 111 in a horizontal direction may belarger than the maximum width 111WC of the plurality of openings 111 ina vertical direction.

As the width 111WR of the plurality of openings 111 in the row directionis increased, the malleable area MA of the back cover 110 may be moreflexibly deformed. Specifically, when the back cover 110 is wound, theback cover 110 may be bent in the column direction of the back cover110, and the stress may be applied so that the plurality of openings 111extends in the column direction. In this case, if the width 111WR of theplurality of openings 111 in the row direction is increased, when theplurality of openings 111 is stretched in the column direction, thewidth 111WC of the plurality of openings 111 in the column direction maybe increased. Further, as the plurality of openings 111 extends in thecolumn direction, the stress applied to the malleable area MA may berelieved. Therefore, the malleable area MA of the back cover 110 may bemore easily wound or unwound by increasing the width 111WR of theplurality of openings 111 in the row direction, and the stress appliedto the malleable area MA may be relieved.

The larger the width 111WC of the plurality of openings 111 in thecolumn direction, the easier it is to form the plurality of openings111. However, when the width 111WC of the plurality of openings 111 inthe column direction is increased, an aperture ratio of the plurality ofopenings 111 may be increased in the malleable area MA. When the width111WC of the plurality of openings 111 in the column direction isincreased, a contact area between the display panel 120 and the backcover 110 which are attached to the malleable area MA may be reduced. Inthis case, if the overlapping area of the display panel 120 and the backcover 110, that is, the contact area between the back cover 110 and thesecond adhesive layer AD2 is reduced, the back cover 110 and the secondadhesive layer AD2 may be separated. Therefore, the adhesiveness betweenthe display panel 120 and the back cover 110 may be controlled byadjusting the width 111WC of the plurality of openings 111 in the columndirection so that the display panel 120 and the back cover 110 are notseparated. Further, the back cover 110 may be designed to have a highflexibility by adjusting the width 111WR of the plurality of openings111 in the row direction.

In this case, in contrast to the malleable area MA, openings 111 are notformed in the first support area PA1 and the second support area PA2.That is, in the first support area PA1 and the second support area PA2,the first fastening holes AH1 and the second fastening holes AH2 arerespectively formed, but the plurality of openings 111, such as thoseformed in the malleable area MA, are not formed. Further, the firstfastening holes AH1 and the second fastening holes AH2 may havedifferent shapes from that of the plurality of openings 111. The firstsupport area PA1 and the second support area PA2, which are to be fixedto the head bar 164 and the roller 151, respectively, may be more rigidthan the malleable area MA. Specifically, as the first support area PA1and the second support area PA2 have a higher rigidity, the firstsupport area PA1 and the second support area PA2 may be more firmlyfixed to the head bar 164 and the roller 151. Therefore, the displayunit DP may be fixed to the roller 151 and the head bar 164 of thedriving unit MP to be moved in and out of the housing unit HP inaccordance with the operation of the driving unit MP.

In the display device 100 according to an exemplary embodiment of thepresent disclosure, the back cover 110 with the plurality of openings111 formed therein may be disposed on the rear surface of the displaypanel 120 to support and protect the display panel 120. The back cover110 may be formed of a metal or plastic material to have rigidity. Theplurality of openings 111 may be formed in the malleable area MA of theback cover 110 where the display panel 120 is disposed to enhance theflexibility of the back cover 110. Therefore, in a fully unwound statein which the display unit DP of the display device 100 is disposedoutside the housing unit HP, the back cover 110 formed of a rigidmaterial to have a high rigidity may support the display panel 120 to bespread flat. In contrast, in a fully wound state in which the displayunit DP of the display device 100 is accommodated in the housing unitHP, the back cover 110 having a high flexibility due to the plurality ofopenings 111 may be wound around the roller 151 together with thedisplay panel 120 to be accommodated.

Further, in the display device 100 according to an exemplary embodimentof the present disclosure, the width 111WR of the plurality of openings111 in the row direction may be adjusted so that the back cover 110 hasa higher flexibility to relieve the stress applied when the back cover110 is wound. Specifically, when the back cover 110 and the displaypanel 120 are wound around the roller, the back cover 110 may be bent inthe column direction, and the stress may be applied such that theplurality of openings 111 extends in the column direction. The pluralityof openings 111 may be formed to have a large width 111WR in the rowdirection so that when the back cover 110 and the display panel 120 arewound around the roller 151, the plurality of openings 111 may be easilystretched in the column direction to relieve the stress applied to theback cover 110. Therefore, in the display device 100 according to anexemplary embodiment of the present disclosure, the width 111WR of theplurality of openings 111 in the row direction may be adjusted toenhance the flexibility of the back cover 110, and the back cover 110and the display panel 120 may be easily wound around the roller 151.Further, the plurality of openings 111 may expand in the columndirection to relieve the stress applied to the back cover 110 and thedisplay panel 120 so that the breakage of the display panel 120 may bereduced or prevented.

Further, in the display device 100 according to an exemplary embodimentof the present disclosure, the width 111WC of the plurality of openings111 in the column direction may be adjusted to adjust the adhesivenessbetween the back cover 110 and the display panel 120. Specifically, thedisplay panel 120 may be attached to the malleable area MA of the backcover 110. In this case, the larger the aperture ratio of the pluralityof openings 111 disposed in the malleable area MA, the smaller thecontact area between the display panel 120 and the back cover 110.Therefore, the adhesiveness between the display panel 120 and the backcover 110 may be reduced. However, in the display device 100 accordingto an exemplary embodiment of the present disclosure, the width 111WC ofthe plurality of openings 111 of the back cover 110 in the columndirection may be formed to be small to reduce the aperture ratio of theplurality of openings 111 and increase the contact area between thedisplay panel 120 and the back cover 110. As the contact area betweenthe display panel 120 and the back cover 110 is increased, theadhesiveness between the display panel 120 and the back cover 110 may beenhanced. Further, in the display device 100 according to an exemplaryembodiment of the present disclosure, the width 111WC of the pluralityof openings 111 in the column direction may be adjusted to ensure apredetermined level or higher of the adhesiveness between the back cover110 and the display panel 120 to prevent or mitigate a potentialseparation between the back cover 110 and the display panel 120.

<A plurality of Malleable Areas and a Plurality of Support Areas of BackCover>

FIG. 8A is a plan view of a display unit of a display device accordingto another exemplary embodiment of the present disclosure. FIG. 8B is aplan view of a back cover of a display device according to anotherexemplary embodiment of the present disclosure. FIGS. 9A to 9C arecross-sectional views of a display device according to another exemplaryembodiment of the present disclosure. Shapes of a back cover 810 and aroller 851 are different, but other components of a display deviceaccording to an example embodiment of FIGS. 8A to 9C are substantiallythe same as the display device 100 of FIGS. 1 to 7B so that a redundantdescription will be omitted. Further, for the convenience ofdescription, in FIGS. 9A to 9C, only a housing unit HP, a roller 851, aflexible film 130, a printed circuit board 140, and a back cover 810 areillustrated.

First, as illustrated in FIGS. 8A and 8B, the back cover 810 may includea plurality of support areas PA and a plurality of malleable areas MA.In the plurality of support areas PA, a plurality of openings 111 is notdisposed. In the plurality of malleable areas MA, a plurality ofopenings 111 is disposed. Specifically, a first support area PA1, afirst malleable area MA1, a third support area PA3, a second malleablearea MA2, a fourth support area PA4, a third malleable area MA3, and asecond support area PA2 may be sequentially disposed from the uppermostend to the lowermost end of the back cover 810.

As described above in detail with reference to FIGS. 1 to 7B, the firstsupport area PA1 may be an uppermost area of the back cover 810. Thefirst support area PA1 is an area which may be fastened with the headbar 164 via a first fastening hole AH1 provided in the first supportarea PA1. A screw SC may pass through a first fastening hole AH1 tofasten the first support area PA1 with the head bar 164.

The first malleable area MA1 may be an area extending from the firstsupport area PA1 to a lower side of the back cover 810. The firstmalleable area MA1 may suppress a wrinkle phenomenon, in which a surfaceof the back cover 810 is bent as the head bar 164 and the first supportarea PA1 are fastened with each other, from spreading to the entiresurface of the back cover 810.

Specifically, when the first support area PA1 and the head bar 164 arefastened with each other, a stress from the screw SC may be concentratedon a part of the first support area PA1 in which the first fasteninghole AH1 is formed. Further, there may be a difference in stress betweenthe part of the first support area PA1 in which the first fastening holeAH1 is formed and the remaining part of the first support area PA1 inwhich the first fastening hole AH1 is not formed so that the surface ofthe back cover 810 may be bent. However, since the plurality of openings111 is disposed in the first malleable area MA1 extending from the firstsupport area PA1, the first malleable area MA1 may have a relativelyhigher flexibility than the first support area PA1. Therefore, the firstmalleable area MA1 may be flexibly deformed to relieve the stressconcentrated on the first fastening hole AH1 of the first support areaPA1. Therefore, even though the wrinkle phenomenon may be generated inthe first support area PA1, the first malleable area MA1 may suppressthe wrinkle phenomenon from propagating to the entire surface of theback cover 810.

The third support area PA3 may be an area extending from the firstmalleable area MA1 to a lower side of the back cover 810. The thirdsupport area PA3 is an area to which the display panel 120 may beattached. Specifically, a part of an upper end of the display panel 120may be attached to the third support area PA3.

When the back cover 810 is fully wound, the third support area PA3 maybe an area which is disposed in the housing unit HP, but is not woundaround the roller 851. For example, in the fully wound state, the firstsupport area PA1 of the back cover 810 may be disposed in the openingHPO of the housing unit HP and the second support area PA2, the thirdmalleable area MP3, the fourth support area PA4, and the secondmalleable area MA2 of the back cover 810 may be wound around the roller851. The third support area PA3 and the first malleable area MA1disposed between the second malleable area MA2 wound around the roller851 and the first support area PA1 disposed in the opening HPO of thehousing unit HP may maintain a flat state. Therefore, even in the fullywound state, the third support area PA3 may maintain a flat state in thehousing unit HP without being wound around or unwound from the roller851, so that there may not be a need to ensure the flexibility of thethird support area PA3 by forming the plurality of openings 111.

Therefore, since the plurality of openings 111 is not formed in thethird support area PA3, the adhesiveness between the third support areaPA3 and the display panel 120 may be enhanced. Specifically, the contactarea between the third support area PA3 and the second adhesive layerAD2 may be increased so that the adhesiveness may be enhanced.Therefore, the adhesiveness between the third support area PA3, thesecond adhesive layer AD2, and the display panel 120 may be enhanced, sothat the display panel 120 and the third support area PA3 may be firmlyfixed to each other. Therefore, the adhesiveness between the back cover810 and the display panel 120 may be enhanced in the third support areaPA3. In addition, when the back cover 810 and the display panel 120 arewound, the separation of the back cover 810 and the display panel 120due to the resulting stress may be minimized or prevented.

Moreover, since the plurality of openings 111 is not formed in the thirdsupport area PA3, the rigidity in the third support area PA3 of the backcover 810 may be enhanced. The plurality of openings 111 may flexiblyexpand or contact with respect to the stress and enhance the flexibilityof the back cover 810. However, the plurality of openings 111 forenhancing the flexibility is not disposed in the third support area PA3,and the third support area PA3 may be formed of a rigid material so thatthe third support area PA3 may have a higher rigidity as compared withthe plurality of malleable areas MA. Therefore, the third support areaPA3 with an enhanced rigidity may protect the display panel 120 from theexternal impact and maintain the display panel 120 to be flat.

The second malleable area MA2 may be an area extending from the thirdsupport area PA3 to a lower side of the back cover 810. The secondmalleable area MA2 is an area in which a plurality of openings 111 maybe disposed and to which the display panel 120 may be attached.Specifically, the remaining part of the display panel 120 other than thepart of the display panel 120 is attached to the third support area PA3may be attached to the second malleable area MA2. Therefore, the displaypanel 120 may be attached to the third support area PA3 and the secondmalleable area MA2.

When the display unit DPa is wound around the roller 851 (see, e.g.,FIGS. 9A to 9C) so that the display unit DPa is accommodated in thehousing unit HP, the second malleable area MA2 of the back cover 810 andthe lower end and portions of the display panel 120 attached to thesecond malleable area MA2 may be wound around the roller 851. In thiscase, in the second malleable area MA2 of the back cover 810, theplurality of openings 111 may be formed so that the second malleablearea MA2 may have a high flexibility and may be easily wound around theroller 851 together with the display panel 120. The second malleablearea MA2 may perform the substantially same function as the examplemalleable area MA described above with reference to FIGS. 1 to 7B.

The fourth support area PA4 may be an area extending from the secondmalleable area MA2 to the lower side of the back cover 810. A flexiblefilm 130 which may be connected to one end of the display panel 120 anda printed circuit board 140 may be attached to the fourth support areaPA4.

To protect the flexible film 130 and the printed circuit board 140, thefourth support area PA4 may allow the flexible film 130 and the printedcircuit board 140 to be wound around the roller 851 in a planar shape,rather than a curved shape. Further, a part of the roller 851 may beformed to have a planar shape, corresponding to the fourth support areaPA4. Detailed description of this example configuration is providedbelow with reference to FIGS. 9A to 9C.

The third malleable area MA3 may be an area extending from the fourthsupport area PA4 to a lower side of the back cover 810. A plurality ofopenings 111 may be disposed in the third malleable area MA3. The thirdmalleable area MA3, when unwound, may extend to dispose the display areaAA of the display panel 120 outside of the housing unit HP. For example,when the back cover 810 and the display panel 120 are fully unwound, thesecond support area PA2 of the back cover 810 connected to the roller851 to the fourth support area PA4, to which the flexible film 130 andthe printed circuit board 140 are attached, may remain disposed in thehousing unit HP. When the back cover 810 and the display panel 120 arefully unwound, the second malleable area MA2 and the third support areaPA3, to which the display panel 120 is attached, may be disposed outsidethe housing unit HP. In this case, if a combined length of the secondsupport area PA2 fixed to the roller 851, the third malleable area MA3,and the fourth support area PA4 is smaller than a length from the secondsupport area PA2 to the opening HPO of the housing unit HP, a part ofthe second malleable area MA2 to which the display panel 120 is attachedmay remain disposed in the housing unit HP. If a part of the lower endof the display area AA of the display panel 120 is disposed in thehousing unit HP, it may be difficult to view displayed images.Therefore, the combined length of the second support area PA2 fixed tothe roller 851, the third malleable area MA3, and the fourth supportarea PA4 may be designed to be at least equal to the length from thesecond support area PA2 fixed to the roller 851 to the opening HPO ofthe housing unit HP.

The second support area PA2 may extend from the third malleable area MA3to the lower side of the back cover 810. As described above in detailwith reference to FIGS. 1 to 7B, the second support area PA2 may be alowermost area of the back cover 810. The second support area PA2 may befastened with the roller 851 via second fastening holes AH2.

FIG. 9A is a cross-sectional view in a state in which the back cover 810is fully unwound from the roller 851. FIG. 9B is a cross-sectional viewin a state in which the second support area PA2, the third malleablearea MA3, and the fourth support area PA4 of the back cover 810 arewound around the roller 851. FIG. 9C is a cross-sectional view in astate in which the second support area PA2, the third malleable areaMA3, the fourth support area PA4, and the second malleable area MA2 ofthe back cover 810 are wound around the roller 851.

As shown in FIG. 9A, the roller 851 may be generally cylindrical, but apart thereof may be flat. That is, a part of an outer circumferentialsurface of the roller 851 may be formed to be flat, and the remainingpart of the outer circumferential surface may be formed to be curved.

The second support area PA2 may be fastened with the flat portion of theroller 851. When the back cover 810 is in the fully unwound state,except for the second support area PA2 fastened with the roller 851, theremaining portion of the back cover 810 extending from the secondsupport area PA2 may be flat.

A cover unit CP may be further disposed on the flexible film 130 and theprinted circuit board 140 disposed in the third support area PA3. Thecover unit CP may be disposed to cover the flexible film 130 and theprinted circuit board 140, and may be formed to have a convex shape. Thecover unit CP may protect the flexible film 130 and the printed circuitboard 140, and may be formed of an insulating material, such as resin,but is not limited thereto.

As described above in detail with reference to FIGS. 8A and 8B, when theback cover 810 is in the fully unwound state, the third malleable areaMA3 and the fourth support area PA4 of the back cover 810 are disposedin the housing unit HP, and the second malleable area MA2 may bedisposed outside the housing unit HP.

Next, as shown in to FIG. 9B, the second support area PA2, the thirdmalleable area MA3, and the fourth support area PA4 of the back cover810 may be wound around the roller 851, and the second malleable areaMA2 extending from the fourth support area PA4 may be unwound.

The second support area PA2 and the fourth support area PA4 may bedisposed on the flat portion of the roller 851, and the third malleablearea MA3 is disposed on the curved portion.

The fourth support area PA4 to which the printed circuit board 140 andthe flexible film 130 are attached may be wound on the flat portion ofthe roller 851 so that the fourth support area PA4, the printed circuitboard 140, and the flexible film 130 maintain a flat state without beingbent. Therefore, the flexible film 130 and the printed circuit board 140may always maintain a flat state regardless of the winding or unwindingof the display unit DPa, thereby preventing or mitigating any damagethat may be caused by the flexible film 130 and the printed circuitboard 140 being bent.

Next, as illustrated in FIG. 9C, a part of the second malleable area MA2may be further wound around the roller 851 in addition to the secondsupport area PA2, the third malleable area MA3, and the fourth supportarea PA4 of the back cover 810 being wound around the roller 851.

A part of the second malleable area MA2 may be wound to overlap a curvedportion of the roller 851. That is, the part of the second malleablearea MA2 may be wound on the third malleable area MA3 that is wound inthe curved portion of the roller 851, and may be bent along the curvedshape of the roller 851.

Another part of the second malleable area MA2 may be wound to overlap aflat portion of the roller 851. This part of the second malleable areaMA2 may be wound on the second support area PA2 and the fourth supportarea PA4 that are wound in the flat portion of the roller 851, and maybe bent like the part of the second malleable area MA2 wound on thethird malleable area MA3.

Specifically, the second malleable area MA2 may be wound around theroller 851 to cover the fourth support area PA4. In this case, the coverunit CP may be disposed between the second malleable area MA2 and thefourth support area PA4. Therefore, the second malleable area MA2 may bewound to cover the cover unit CP of the fourth support area PA4 and maybe bent along the shape of the cover unit CP. The cover unit CP may havea curved surface so that the second malleable area MA2 may also be bentalong the curved surface. Specifically, the curved shape of an uppersurface of the cover unit CP may have a curved shape corresponding tothe roller 851, so that a cross-section of the second malleable area MA2wound around the roller 851 may have a substantially circular shape.

In the display device according to another exemplary embodiment of thepresent disclosure, a wrinkle phenomenon due to the fastening of thefirst support area PA1 and the head bar 164 may be minimized. The firstsupport area PA1 of the back cover 810 may have the first fasteningholes AH1 formed therein, and may be fastened with the head bar 164.Screws SC may pass through the first fastening holes AH1 of the firstsupport area PA1 to be fastened with the head bar 164. Stress may beconcentrated on or around the first fastening holes AH1. There may be adifference in the amount of stress between the part of the first supportarea PA1 in which the first fastening holes AH1 are formed and theremaining part of the first support area PA1 in which no first fasteninghole AH1 is formed. This may result in a wrinkle phenomenon in which thesurface of the first support area PA1 may be bent. Therefore, in thedisplay device according to another exemplary embodiment of the presentdisclosure, the first malleable area MA1 in which the plurality ofopenings 111 is formed may be disposed at a lower end of the firstsupport area PA1 of the back cover 810 to prevent or suppress thewrinkle phenomenon that may be generated in the first support area PA1from spreading to the entire surface of the back cover 810. That is, thefirst malleable area MA1 has a plurality of openings 111 disposedtherein so that it has a higher flexibility than the first support areaPA1. Therefore, the plurality of openings 111 in the first malleablearea MA1 may be flexibly deformed to relieve the stress concentrated onthe first fastening holes AH1 of the first support area PA1. Therefore,the propagation of the wrinkle phenomenon generated in the first supportarea PA1 to the remaining area of the back cover 810 may be minimized.

Further, in the display device according to another exemplary embodimentof the present disclosure, the adhesiveness between the back cover 810and the display panel 120 may be enhanced by the third support area PA3.Specifically, the third support area PA3 may always maintain a flatstate regardless of whether the back cover 810 is in a fully wound orfully unwound state. Therefore, the third support area PA3 may be anarea which is not wound around the roller 851 and may not need toinclude the plurality of openings 111 to ensure the flexibility. With noopenings 111 formed thereon, a contact area of the third support areaPA3 with the second adhesive layer AD2 may be increased, and theadhesiveness with the second adhesive layer AD2 may be enhanced. If theadhesiveness between the second adhesive layer AD2 and the back cover810 is weak, the back cover 810 and the display panel 120 may slide dueto the slip phenomenon and the back cover 810 may be separated from thedisplay panel 120 when the back cover 810 and the display panel 120 arewound. Therefore, in the display device according to another exemplaryembodiment of the present disclosure, the plurality of openings 111 isnot formed in the third support area PA3 which may always maintain aflat state so that the contact area and the adhesiveness between thethird support area PA3 and the second adhesive layer AD2 may beenhanced. Since the adhesiveness between the third support area PA3 andthe second adhesive layer AD2 is enhanced, the adhesiveness between thethird support area PA3 and the display panel 120 is also enhanced.Therefore, excessive slip due to the stress applied, e.g., when thedisplay panel 120 and the back cover 810 are wound, and the resultingseparation of the display panel 120 from the back cover 810 may beprevented or minimized.

Further, in the display device according to another exemplary embodimentof the present disclosure, when the display unit DPa is fully unwound,the back cover 810 may maintain a flat state due to the third supportarea PA3, and the rigidity may be ensured. That is, when the displayunit DPa is fully unwound, the third support area PA3 allows the displaypanel 120 to maintain a flat state. The third support area PA3 may havea high rigidity as compared with the plurality of malleable areas MA inwhich the plurality of openings 111 is formed. Thus, the third supportarea PA3 may allow the display panel 120 to maintain a flat state in thefully unwound state. Further, the third support area PA3 may have a highimpact resistance against the impact from the outside of the displayunit DPa to protect the back cover 810 and the display panel 120attached to the back cover 810.

Further, in the display device according to another exemplary embodimentof the present disclosure, the fourth support area PA4 may alwaysmaintain a flat state to prevent or minimize any damage to the flexiblefilm 130 and the printed circuit board 140 which are attached to thefourth support area PA4. The fourth support area PA4 is an area to whichthe flexible film 130 and the printed circuit board 140 may be attachedand which may always maintain a flat state. Therefore, since the fourthsupport area PA4 maintains a flat state, like the third support areaPA3, the plurality of openings 111 does not need to be formed therein.Specifically, when the back cover 810 is wound around the roller 851,the back cover 810 may be wound while being bent along the shape of theroller 851. Therefore, in the display device according to anotherexemplary embodiment of the present disclosure, a part of the roller 851around which the fourth support area PA4 is to be wound may be formed tobe flat so that the fourth support area PA4 may be wound flat around theroller 851. Even though the fourth support area PA4 may be wound aroundthe roller 851, the fourth support area PA4 may always maintain a flatstate, so that the flexible film 130 and the printed circuit board 140attached to the fourth support area PA4 may also maintain a flat state.For example, when the display unit DPa is fully unwound, the flexiblefilm 130 and the printed circuit board 140 may maintain the flat statedue to the fourth support area PA4 having a high rigidity. On the otherhand, when the display unit DPa is fully wound, the flexible film 130and the printed circuit board 140 may be seated in a flat portion of theroller 851 to maintain the flat state. Therefore, in the display deviceaccording to another exemplary embodiment of the present disclosure, theflexible film 130 and the printed circuit board 140 are not repeatedlybent so that the damage of the flexible film 130 and the printed circuitboard 140 may be minimized.

<“Inverted L” Shaped Head Bar>

FIG. 10 is a schematic cross-sectional view for explaining a head barand a display unit of a display device according to another exemplaryembodiment of the present disclosure. A shape of a head bar 1064 of thedisplay device may be different from that in the other exampleembodiments described above, but other components of the example displaydevice of FIG. 10 may be substantially the same as the example displaydevice of FIGS. 8A to 9C. Thus, a redundant description will be omitted.

As illustrated in FIG. 10, a head bar 1064 may be disposed at anuppermost end of the display unit DPa to enclose a portion of a frontsurface and a portion of a rear surface of the display unit DPa. Thehead bar 1064 may be partially bent to have an “inverted L” shape.

The head bar 1064 may include a first head bar 1064 a and a second headbar 1064 b. The first head bar 1064 a may cover a portion of the frontsurface of the display unit DPa. The first head bar 1064 a may bedisposed on the front surface of the display unit DPa so as to cover afirst support area PA1 and a first malleable area MA1 of a back cover810. A part of the first head bar 1064 a which overlaps the firstsupport area PA1 may extend in a direction perpendicular to the rearsurface of the display panel 120. The remaining portion of the firsthead bar 1064 a which overlaps the first malleable area MA1 may extendin a direction parallel to the front surface of the display panel 120.Therefore, the part of the first head bar 1064 a overlapping the firstsupport area PA1 and the remaining portion overlapping the firstmalleable area MA1 may form an approximately 90 degree angle and have an“inverted L” shape. Therefore, the first support area PA1 and the firstmalleable area MA1 of the back cover 810 overlapping the first head bar1064 a may also be bent to have an “inverted L” shape. Even though hefirst head bar 1064 a is illustrated, for example in FIG. 10, to coverthe first support area PA1 and the first malleable area MA1, the firsthead bar 1064 a may further extend from the first malleable area MA1 tocover the third support area PA3, depending on the design, and is notlimited to these examples.

The second head bar 1064 b may cover the rear surface of the displayunit DPa. The second head bar 1064 b may be disposed in the display unitDPa so as to cover the first support area PA1, the first malleable areaMA1, and a portion of the third support area PA3 of the back cover 810.A part of the second head bar 1064 b which overlaps the first supportarea PA1 may extend in a direction perpendicular to the rear surface ofthe display panel 120. The remaining portion of the second head bar 1064b which overlaps the first malleable area MA1 and the third support areaPA3 may extend in a direction parallel to the rear surface of thedisplay panel 120. Therefore, the part of the second head bar 1064 boverlapping the first support area PA1 and the remaining portionoverlapping the first malleable area MA1 and the third support area PA3may form an approximately 90 degree angle and have an “inverted L”shape. Therefore, the first support area PA1, the first malleable areaMA1, and the third support area PA3 of the back cover 810 overlappingthe second head bar 1064 b may also be bent to have an “inverted L”shape.

Therefore, with the head bar 1064 bent to have a “inverted L” shape, thewrinkle phenomenon may be relieved. Specifically, with the first supportarea PA1 and the head bar 1064 are fastened with each other, a stressfrom the screw SC is concentrated on a part of the first support areaPA1 in which the first fastening hole AH1 is formed. Therefore, thewrinkle phenomenon may be generated in the first support area PA1 due tothe generated stress. In this case, as the first support area PA1 andthe first malleable area MA1 may be fastened with the head bar 1064which is partially bent, the first malleable area MA1 may also be bentto have the “inverted L” shape as does the head bar 1064. Therefore, thestress concentrated on the first fastening holes AH1 of the firstsupport area PA1 may be relieved, thereby preventing or minimizing anywrinkle phenomenon generated in the first support area PA1 frompropagating to the entire surface of the back cover 810.

Further, in the display device according to another exemplary embodimentof the present disclosure, the head bar 1064 may include the first headbar 1064 a and the second head bar 1064 b. The first head bar 1064 a andthe second head bar 1064 b may be partially bent to have an “inverted L”shape. Parts of the first head bar 1064 a and the second head bar 1064 bwhich overlap the first support area PA1 may extend in a directionperpendicular to the rear surface of the display panel 120. Theremaining parts of the first and second head bars 1064 a, 1064 b whichoverlap the first malleable area MA1 may extend in a direction parallelto the front surface and the rear surface of the display panel 120.Therefore, as the parts and the remaining part of the first head bar1064 a and the second head bar 1064 b extend in different directions,the first head bar 1064 a and the second head bar 1064 b may have an“inverted L” shape. The first support area PA1 and the first malleablearea MA1 of the back cover 810 disposed between the first head bar 1064a and the second head bar 1064 b may also be bent to have an “invertedL” shape in accordance with the shapes of the first head bar 1064 a andthe second head bar 1064 b. Therefore, as the first support area PA1 andthe first malleable area MA1 are bent, the stress concentrated on thefirst fastening holes AH1 in the first support area PA1 may be relieved.Therefore, the first support area PA1 and the first malleable area MA1may be bent in the “inverted L” shaped head bar 1064, and thepropagation of any wrinkle phenomenon generated in the first supportarea PA1 to the remaining area of the back cover 810 may be minimized.

<Various Shapes of Plurality of Openings of Back Cover>

FIGS. 11A to 11C are plan views of back covers of a display deviceaccording to various exemplary embodiments of the present disclosure.The shapes of a plurality of openings 1111 a, 1111 b, and 1111 c aredifferent from those in other example embodiments above, but otherconfigurations of the example back covers 1110 a, 1110 b, and 1110 c ofFIGS. 11A to 11C may be substantially the same as the example back cover810 of FIGS. 8A to 9C. Thus, a redundant description will be omitted.

As shown in FIG. 11A, a plurality of openings 1111 a may be disposed ina plurality of malleable areas MA of a back cover 1110 a. The pluralityof openings 1111 a may have an oval shape. Specifically, the pluralityof openings 1111 a may be formed to have an oval shape having a majoraxis in a row direction and a minor axis in a column direction.

As illustrated in FIG. 11B, a plurality of openings 1111 b may bedisposed in a plurality of malleable areas MA of a back cover 1110 b.The plurality of openings 1111 b may have a ribbon shape. Specifically,a width of the plurality of openings 1111 b in a column direction maydecrease from both ends of the plurality of openings 1111 b to thecenter of the plurality of openings 1111 b. Therefore, the plurality ofopenings 1111 b may have a ribbon-like shape.

As shown in FIG. 11C, a plurality of openings 1111 c may be disposed ina plurality of malleable areas MA of a back cover 1110 c. The pluralityof openings 1111 c may have a dumbbell shape. Specifically, the width ofthe plurality of openings 1111 c in the column direction may decreasetoward the center of the plurality of openings 1111 c. The width of theplurality of openings 1111 c in the column direction may increasefarther away from the center of the plurality of openings 1111 c. Inthis case, both ends of the plurality of openings 1111 c in the rowdirection may have a round shape. Therefore, the plurality of openings1111 c may have a dumbbell-like shape.

FIGS. 11A to 11C illustrate the plurality of example openings 1111 a,1111 b, and 1111 c with an oval shape, a ribbon shape, and a dumbbellshape. However, if a width of the plurality of openings 1111 a, 1111 b,and 1111 c in the row direction is larger than a width in the columndirection, the shape of the openings is not limited to these specificexamples. For example, the plurality of openings 1111 a, 1111 b, and1111 c may be designed to have various other shapes, such as arectangular shape or a rhombus shape.

Even though FIGS. 11A to 11C illustrate various shapes of the pluralityof example openings 1111 a, 1111 b, and 1111 c in the configuration ofthe example back cover 810 illustrated in FIG. 8B, the plurality ofexample openings 1111 a, 1111 b, and 1111 c of FIGS. 11A to 11C may alsobe applied to the example back cover 110 illustrated in FIG. 7A, andembodiments are not limited thereto.

Further, even though FIGS. 11A to 11C illustrate that the plurality ofexample openings 1111 a, 1111 b, and 1111 c of the back covers 1110 a,1110 b, and 1110 c has the same respective shapes, the plurality ofopenings 1111 a, 1111 b, and 1111 c of the back covers 1110 a, 1110 b,and 1110 c may have different shapes.

In display devices according to still another exemplary embodiment ofthe present disclosure, the respective shapes of the plurality ofopenings 1111 a, 1111 b, and 1111 c of the back covers 1110 a, 1110 b,and 1110 c may vary to minimize the stress applied to the display panel120 and flexibly deform the back covers 1110 a, 1110 b, and 1110 c.Specifically, as the plurality of openings 1111 a, 1111 b, and 1111 c isformed in the back covers 1110 a, 1110 b, and 1110 c, when the backcovers 1110 a, 1110 b, and 1110 c are wound or unwound, the back covers1110 a, 1110 b, and 1110 c may be flexibly deformed. The plurality ofopenings 1111 a, 1111 b, and 1111 c may be flexibly deformed so that thestress generated at the time of winding the back covers 1110 a, 1110 b,and 1110 c may be dispersed, and the stress applied to the display panel120 disposed in the plurality of malleable areas MA of the back covers1110 a, 1110 b, and 1110 c may also be minimized. In this case, theplurality of openings 1111 a, 1111 b, and 1111 c may be formed such thattheir boundaries are not parallel to each other in the row direction todisperse the stress. Specifically, when the back covers 1110 a, 1110 b,and 1110 c are wound in the column direction of the plurality ofopenings 1111 a, 1111 b, and 1111 c, the stress may be applied in adirection of vertically extending the plurality of openings 1111 a, 1111b, and 1111 c, that is, in a column direction. The stress may beconcentrated on the boundaries of the plurality of openings 1111 a, 1111b, and 1111 c extending in a direction parallel to the row direction. Inthis case, if the boundaries of the plurality of openings 1111 a, 1111b, and 1111 c in the row direction are not parallel to the rowdirection, that is, if the boundaries of the plurality of openings 1111a, 1111 b, and 1111 c extend in a direction different from the rowdirection, normal directions of the plurality of openings 1111 a, 1111b, and 1111 c in the boundaries may be defined in various directions,and the stress may also be dispersed in various directions.

For example, if the plurality of openings 1111 a has an oval shape as inthe example back cover 1110 a of FIG. 11A, the boundaries of theplurality of openings 1111 a have a curved surface with respect to therow direction. Therefore, when the stress is applied to the plurality ofopenings 1111 a having an oval shape, the stress may be dispersed invarious directions along the normal direction of the curved surfacewhich is the boundary of the plurality of openings 1111 a.

Next, if the plurality of openings 1111 b has a ribbon shape as in theexample back cover 1110 b of FIG. 11B, the boundaries of the pluralityof openings 1111 b in the row direction have inclined surfaces.Therefore, when the stress is applied to the plurality of openings 1111b having a ribbon shape, the stress may be dispersed along the inclinedsurfaces which are the boundaries of the plurality of openings 1111 b.

Finally, if the plurality of openings 1111 c has a dumbbell shape as inthe example back cover 1110 c of FIG. 11C, the boundaries of theplurality of openings 1111 c in the row direction have curved surfaces.Therefore, when the stress is applied to the plurality of openings 1111c having a dumbbell shape, the stress may be dispersed along a normaldirection of the curved surfaces which are the boundaries of theplurality of openings 1111 c. If both ends of the plurality of openings1111 c are relatively narrow and angled, the stress may be concentratedon both ends of the plurality of openings 1111 c. In this case, theplurality of openings 1111 c having a dumbbell shape may be formed suchthat both ends have curved surfaces, and both ends of the plurality ofopenings 1111 c may have a larger width in the column direction than thecenter portion of the plurality of openings 1111 c. Therefore, in theplurality of openings 1111 c having a dumbbell shape, widths of bothends in the column direction may be formed to be relatively large and tohave a curved surface so that the concentration of the stress on bothends of the plurality of openings 1111 c may be minimized.

Therefore, in the display device according to still another exemplaryembodiment of the present disclosure, the plurality of openings 1111 a,1111 b, and 1111 c of the back covers 1110 a, 1110 b, and 1110 c may beformed such that the boundaries of the plurality of openings 1111 a,1111 b, and 1111 c in the row direction are not parallel to the rowdirection. Therefore, the stress which is applied to expand theplurality of openings 1111 a, 1111 b, and 1111 c in the column directionat the time of winding the back covers 1110 a, 1110 b, and 1110 c may bedispersed.

<ReinforCement Area for Reinforcing Rigidity of Back Cover>

FIG. 12 is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure. With theexception of an edge reinforcement area ERA being added, otherconfigurations of an example back cover 1210 of FIG. 12 may besubstantially the same as those of the example back covers 810 of FIGS.8A to 9C. Thus, a redundant description will be omitted.

As illustrated in FIG. 12, in a back cover 1210, edge reinforcementareas ERA may be disposed in a left edge and a right edge of theplurality of malleable areas MA. The edge reinforcement areas ERA mayhave a plurality of openings 111 a with a smaller width in a columndirection than the plurality of openings 111 in the plurality ofmalleable areas MA. The edge reinforcement area ERA may have a higherrigidity than the plurality of malleable areas MA. Therefore, the edgereinforcement area ERA may be disposed in the back cover 1210 so thatthe rigidity at the left edge and the right edge of the back cover 1210may be enhanced.

A plurality of openings 111 a disposed in the edge reinforcement areasERA may be formed to extend from a plurality of openings 111 closest tothe edge reinforcement areas ERA among the plurality of openings 111disposed in the plurality of malleable areas MA. The plurality ofopenings 111 a of the edge reinforcement areas ERA may have a smallerwidth in the column direction than the plurality of openings 111 of themalleable area MA. Therefore, an aperture ratio of the edgereinforcement areas ERA may be lower than an aperture ratio of theplurality of malleable areas MA. Therefore, the rigidity of the backcover 1210 may be further enhanced in the edge reinforcement areas ERA.

In the back cover 1210 according to another exemplary embodiment of thepresent disclosure, an edge reinforcement areas ERA may have a loweraperture ratio than the plurality of malleable areas MA. The edgereinforcement areas ERA may be disposed at the left edge and the rightedge of the plurality of malleable areas MA, respectively, to enhancethe rigidity at the sides of the back cover 1210. The plurality ofopenings 111 a disposed in the edge reinforcement areas ERA disposed atthe left edge and the right edge of the plurality of malleable areas MAmay have a smaller width in the column direction than the plurality ofopenings 111 in the plurality of malleable area MA. Therefore, anaperture ratio of the edge reinforcement areas ERA may be lower than anaperture ratio of the plurality of malleable areas MA, and the rigidityof the edge reinforcement areas ERA may be enhanced. Accordingly, theedge reinforcement areas ERA may enhance the rigidity at the left edgeand the right edge of the back cover 1210, thus helping to maintain theback cover 1210 flat without being bent even when external impacts areapplied to the left edge and the right edge of the back cover 1210.Therefore, in the display device according to another exemplaryembodiment of the present disclosure, the edge reinforcement areas ERAmay be disposed at the left edge and the right edge of the back cover1210 to enhance the overall rigidity of the back cover 1210 and protectthe display panel 120 from the external impacts.

FIG. 13 is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure. With theexception of a plurality of reinforcement areas RA being added, otherconfigurations of the example back cover 1310 of FIG. 13 may besubstantially the same as that of the example back cover 810 of FIGS. 8Ato 9C. Thus, a redundant description will be omitted.

As shown in FIG. 13, a plurality of reinforcement areas RA may beprovided in the second malleable area MA2 of the back cover 1310. Theplurality of reinforcement areas RA may be spaced apart from each otherin the second malleable area MA. Specifically, the plurality ofreinforcement areas RA may extend in a row direction in the secondmalleable area MA2, that is, in a length direction of the plurality ofopenings 111. The plurality of reinforcement areas RA may be spacedapart from each other in the column direction.

The plurality of openings 111 may be disposed in the remaining areas ofthe second malleable area MA2 except the plurality of reinforcementareas RA. That is, the plurality of openings 111 may be disposed betweenthe plurality of reinforcement areas RA. The plurality of openings 111may be disposed between the third support area PA3 and a reinforcementarea RA closest to the third support area PA3 among the plurality ofreinforcement areas RA. The plurality of openings 111 may also bedisposed between the fourth support area PA4 and a reinforcement area RAclosest to the fourth support area PA4 among the plurality ofreinforcement areas RA.

In this case, a first width W1 of the plurality of reinforcement areasRA in the column direction may be smaller than a second width W2 whichis a distance between the plurality of reinforcement areas RA in thecolumn direction. Specifically, the plurality of reinforcement areas RAmay be areas in which the plurality of openings 111 is not disposed andwhich have a higher rigidity than parts of the second malleable area MA2in which the plurality of openings 111 is disposed. Therefore, thelarger the first width W1 of the plurality of reinforcement areas RA inthe column direction, the higher the rigidity of the back cover 1310. Onthe other hand, parts of the second malleable area MA2 between theplurality of reinforcement areas RA in which the plurality of openings111 is disposed may have a higher flexibility than the plurality ofreinforcement areas RA. Therefore, the larger the second width W2between the plurality of reinforcement areas RA, the higher theflexibility of the back cover 1310, so that the back cover 1310 may bemore easily wound or unwound. In summary, the larger the first width W1,the higher the rigidity of the back cover 1310 and the lower theflexibility. Further, the larger the second width W2, the higher theflexibility of the back cover 1310 and the lower the rigidity.

However, the second malleable area MA2 may be a portion to which acenter portion or a lower end portion of the display panel 120 may beattached and which is wound around or unwound from the roller 851 to bedisposed inside or outside the housing unit HP. Therefore, in order tomore easily wind or unwind the second malleable area MA2 around theroller 851, the second width W2 between the plurality of reinforcementareas RA may be formed to be larger than the first width W1 of theplurality of reinforcement areas RA in the column direction to ensurethe flexibility of the second malleable area MA2. Further, since theplurality of reinforcement areas RA may be further disposed in thesecond malleable area MA2, the rigidity of the second malleable area MA2may be enhanced. Simultaneously, the first width W1 of the plurality ofreinforcement areas RA in the column direction may be formed to besmaller than the second width W2 between the plurality of reinforcementareas RA to ensure the flexibility of the second malleable area MA2.

In the back cover 1310 according to still another exemplary embodimentof the present disclosure, the plurality of reinforcement areas RA maybe disposed in the second malleable area MA2 of the back cover 1310, tosimultaneously ensure the flexibility and the rigidity of the back cover1310. Specifically, the plurality of reinforcement areas RA may bedisposed in the second malleable area MA2 of the back cover 1310. Theplurality of reinforcement areas RA may be areas where the plurality ofopenings 111 is not disposed. The plurality of reinforcement areas RAmay have a higher rigidity than the second malleable area MA2 in whichthe plurality of openings 111 is disposed. Further, the plurality ofopenings 111 may be disposed between the third support areas PA3 and theadjacent reinforcement area RA, between the plurality of reinforcementareas RA, and between the fourth support area PA4 and the adjacentreinforcement area RA. Parts of the second malleable area MA2 in whichthe plurality of openings 111 is disposed may have a high flexibility.The second malleable area MA2 is an area which may be wound around orunwound from the roller 851 so that a predetermined level of flexibilitymay need to be ensured. Therefore, the first width W1 of the pluralityof reinforcement areas RA having a low flexibility in the columndirection may be formed to be smaller than the second width W2 in thecolumn direction of the areas of the second malleable area MA2 in whichthe plurality of openings 111 is disposed, to enhance the flexibility ofthe second malleable area MA2. Further, in the second malleable areaMA2, the plurality of reinforcement areas RA having a high rigidity isdisposed so that the rigidity of the second malleable area MA2 may alsoenhanced. Therefore, in the back cover 1310 according to anotherexemplary embodiment of the present disclosure, the plurality ofreinforcement areas RA is disposed in the second malleable area MA2 toenhance the rigidity of the back cover 1310 and to protect the backcover 1310 and the display panel 120 from the external impacts. Further,the first width W1 of the plurality of reinforcement areas RA in thecolumn direction may be formed to be smaller than the second width W2between the plurality of reinforcement areas RA to ensure theflexibility of the back cover 1310.

If the first width W1 of the plurality of reinforcement areas RA in thecolumn direction is excessively increased, the plurality ofreinforcement areas RA may interfere with the winding or unwinding ofthe back cover 1310 around the roller 851 and may break the displaypanel 120. Specifically, even though the plurality of reinforcementareas RA may be wound around the roller 851, the flexibility thereof maybe lower than that of the other parts of the malleable area MA2 or ofother malleable areas MA so that it may be more difficult for theplurality of reinforcement areas RA to be flexibly deformed along theshape of the roller 851. Therefore, there may be a limit to how much theplurality of reinforcement areas RA may be bent. Further, if the firstwidth W1 of the plurality of reinforcement areas RA in the columndirection is excessively increased, an upper corner of the plurality ofreinforcement areas RA may interfere with the display panel 120 on theplurality of reinforcement areas RA and may break the display panel 120.Therefore, the first width W1 of the plurality of reinforcement areas RAin the column direction may be appropriately determined based on aradius of the roller 851, and respective thicknesses of the displaypanel 120 and the back cover 1310.

Hereinafter, designing of the width of the plurality of reinforcementareas RA will be described with reference to FIG. 14.

FIG. 14 is a schematic cross-sectional view for explaining a width of areinforcement area of a back cover of a display device according tostill another exemplary embodiment of the present disclosure. For theconvenience of description, in FIG. 14, only a roller 851, a displaypanel 120, a second adhesive layer AD2, and a back cover 1310 areschematically illustrated. Further, for the purpose of this description,cross-sections of the display panel 120, the second adhesive layer AD2,and the back cover 1310 are assumed to have a circular shape, and theback cover 1310, the second adhesive layer AD2, and the display panel120 are assumed to be sequentially disposed on an outer circumferentialsurface of the roller 851.

As illustrated in FIG. 14, a maximum width MW of the plurality ofreinforcement areas RA may be determined based on a radius R of theroller 851, a thickness t1 of the back cover 1310, a thickness t2 of thesecond adhesive layer AD2, and a compressibility a of the secondadhesive layer AD2.

Here, a straight-line length from the center of the roller 851 to theouter circumferential surface of the roller 851 may be defined as aradius R of the roller 851. Further, a straight-line length from thecenter of the roller 851 to an outer circumferential surface of thesecond adhesive layer AD2 which is wound around the roller 851 may bedefined as a first length LN1. In this case, the first length LN1 may becalculated by adding the radius R of the roller 851, the thickness t1 ofthe back cover 1310, and a value obtained by multiplying acompressibility “a” with the thickness t2 of the second adhesive layerAD2. In addition, a straight-line length from the center of the roller851 to an outer circumferential surface of the back cover 1310 which iswound around the roller 851 may be defined as a second length LN2. Inthis case, the second length LN2 may be calculated by adding the radiusR of the roller 851 and the thickness t1 of the back cover 1310.

Next, the maximum width MW of the plurality of reinforcement areas RAmay be calculated based on the first length LN1 and the second lengthLN2. Specifically, the maximum width MW of the plurality ofreinforcement areas RA may be calculated by the following Equation 1:

Maximum width of reinforcementarea=2×[√{(LN1)²−(LN2)²}]=2×[√{(R+t1+t2×a)²−(R+t1)²}]  [Equation 1]

Based on Equation 1, the maximum width MW of the reinforcement area RAmay be obtained by doubling the square root of a value obtained bysubtracting the square of the second length LN2 from the square of thefirst length LN1.

With the back cover 1310 already in a state of being wound around theroller 851 once, a different radius R of the roller 851 may be definedto determine a maximum width MW of the plurality of reinforcement areasRA in a part of the back cover 1310 which is wound a second turn aroundthe roller 851. In this case, the radius R of the roller 851 may bedefined as a radius of an entire member around which the back cover 1310is wound the second turn. For example, in Equation 1, the radius R ofthe roller 851 may be defined differently as a value obtained by addingthe radius R of the roller 851 and the thickness t1 of the back cover1310 to calculate the maximum width MW of the reinforcement area RA inthe part of the back cover 1310 wound the second turn around the roller851.

When the maximum width MW of the plurality of reinforcement areas RAexceeds the value calculated by Equation 1, an upper corner of theplurality of reinforcement areas RA may interfere with the display panel120 on the second adhesive layer AD2. Specifically, because theplurality of reinforcement areas RA may have a lower flexibility thanthat of the plurality of malleable areas MA, the plurality ofreinforcement areas RA may not be flexibly bent along the shape of theroller 851 in a similar manner as the plurality of malleable areas MAand may have a limit as to how much it may be bent. If the width of theplurality of reinforcement areas RA is excessively large, when the backcover 1310 is wound around the roller 851, the upper corner of theplurality of reinforcement areas RA may not be bent along the shape ofthe roller 851, but may protrude to the second adhesive layer AD2 and tothe display panel 120 from the outer circumferential surface of theroller 851. Therefore, the upper corner of the plurality ofreinforcement areas RA may apply excessive stress to the second adhesivelayer AD2 and the display panel 120 so that the display panel 120 may bedamaged. Further, the upper corner of the plurality of reinforcementareas RA may penetrate the second adhesive layer AD2 to be in directcontact with the display panel 120 so that the display panel 120 may bedamaged.

In a display device according to still another exemplary embodiment ofthe present disclosure, in order to ensure the rigidity of the backcover 1310, a plurality of reinforcement areas RA may be disposed in theback cover 1310. Further, the maximum width MW of the plurality ofreinforcement areas RA may be designed in consideration of a radius R ofthe roller 851, a thickness t1 of the back cover 1310, a thickness t2 ofthe second adhesive layer AD2, and a compressibility “a” of the secondadhesive layer AD2. First, the plurality of reinforcement areas RA maybe areas where the plurality of openings 111 is not disposed and mayhave a rigidity higher than that of the malleable areas MA. Therefore,the plurality of reinforcement areas RA may be disposed in a malleablearea MA, e.g., the second malleable area MA2, with a constant intervalto enhance the rigidity of the back cover 1310 in the malleable area MA,and stably support and protect the display panel 120.

In a display device according to still another exemplary embodiment ofthe present disclosure, the maximum widths MW of the plurality ofreinforcement areas RA may be designed such that the upper corner of theplurality of reinforcement areas RA does not interfere with the displaypanel 120. Specifically, the maximum width MW of the plurality ofreinforcement areas RA may be designed in consideration of a radius R ofthe roller 851, a thickness t1 of the back cover 1310, a thickness t2 ofthe second adhesive layer AD2, and a compressibility “a” of the secondadhesive layer AD2. Since the plurality of reinforcement areas RA has alow flexibility due to a high rigidity, when the back cover 1310 iswound around the roller 851, it may be difficult to bend the back cover1310 along the shape of the roller 851 and the back cover 1310 may havea limit as to how much it may be bent. Therefore, when the back cover1310 including the plurality of reinforcement areas RA is wound aroundthe roller 851, the plurality of reinforcement areas RA may not becompletely bent along the shape of the roller 851, and the upper cornerof the plurality of reinforcement areas RA may protrude from the outercircumferential surface of the roller 851 to apply excessive pressure onthe second adhesive layer AD2. In this case, if the width of theplurality of reinforcement areas RA is excessively large, the uppercorner of the plurality of reinforcement areas RA may apply excessivepressure on the second adhesive layer AD2 to reach a rear surface of thedisplay panel 120. If the corner of the plurality of reinforcement areasRA comes in contact with the display panel 120, the display panel 120may be damaged. Therefore, in the display device according to stillanother exemplary embodiment of the present disclosure, the maximumwidth MW of the plurality of reinforcement areas RA may be designed inconsideration of the radius R of the roller 851, the thickness t1 of theback cover 1310, the thickness t2 of the second adhesive layer AD2, andthe compressibility “a” of the second adhesive layer AD2. Further, anydamage of the display panel 120 caused by the plurality of reinforcementareas RA may be prevented or minimized while the plurality ofreinforcement areas RA enhances the rigidity of the back cover 1310.

<Protrusion for Reinforcing Rigidity of Back Cover>

FIG. 15A is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure. FIG. 15Bis a cross-sectional view taken along the line XV-XV′ of FIG. 15A. Withthe exception of protrusions RAP being further provided, otherconfigurations of the example back cover 1510 of FIGS. 15A and 15B aresubstantially the same as the example back cover 1310 of FIG. 13. Thus,a redundant description will be omitted.

As illustrated in FIGS. 15A and 15B, a plurality of protrusions RAP maybe further disposed in the plurality of reinforcement areas RA of theback cover 1510. Specifically, each of the plurality of protrusions RAPmay be disposed to overlap each of the plurality of reinforcement areasRA, respectively, and may extend in a row direction along the pluralityof reinforcement areas RA.

The protrusions RAP may be located on a rear surface of the back cover1510 to which the display panel 120 is not attached. If the protrusionsRAP are located on a front surface of the back cover 1510 to which thedisplay panel 120 is attached, the surface of the display panel 120 maynot be even and may have unevenness due to the protrusions RAP.Therefore, the protrusions RAP may be located on the rear surface of theback cover 1510 to which the display panel 120 is not attached so as notto be in contact with the display panel 120. That is, the protrusionsRAP may be disposed on the rear surface 1510, which is an oppositesurface of the front surface of the back cover 1510 facing the displaypanel 120 in the plurality of reinforcement areas RA.

The protrusions RAP may be formed to be integrated with the plurality ofreinforcement areas RA. For example, the front surface and the rearsurface of the back cover 1510 may be simultaneously etched to form theplurality of openings 111, the plurality of reinforcement areas RA, andthe protrusions RAP in the back cover 1510. Specifically, at the sametime that the plurality of openings 111 in the back cover 1510 isformed, the remaining regions other than the protrusions RAP may beetched to form the protrusions RAP in the area overlapping the pluralityof reinforcement areas RA on the rear surface of the back cover 1510. Bydoing this, the plurality of reinforcement areas RA and the protrusionsRAP may be integrally formed. Alternatively, the protrusions RAP may beseparately attached to the plurality of reinforcement areas RA, but arenot limited thereto.

As described above in detail with reference to FIG. 14, the width of theprotrusions RAP in the column direction may be designed to be equal tothe maximum width MW of the plurality of reinforcement areas RA. If thewidth of the protrusions RAP in the column direction is larger than themaximum width MW of the plurality of reinforcement areas RA, theprotrusions RAP may interfere with the winding or unwinding of the backcover 1510, and corners of the protrusions RAP may interfere with thedisplay panel 120. Therefore, the maximum width of the protrusions RAPin the column direction may be smaller than or equal to the maximumwidth MW of the plurality of reinforcement areas RA in the columndirection.

In the display device according to another exemplary embodiment of thepresent disclosure, the plurality of reinforcement areas RA andprotrusions RAP may be disposed in the back cover 1510 to enhance therigidity of the back cover 1510. Specifically, the plurality ofreinforcement areas RA and the protrusions RAP protruding out of therear surface of the back cover 1510 from the plurality of reinforcementareas RA may be located in the second malleable area MA2 of the backcover 1510. The plurality of reinforcement areas RA and the protrusionsRAP may be areas where the plurality of openings 111 is not disposed andmay have a rigidity higher than that of the plurality of malleable areasMA. Therefore, the plurality of reinforcement areas RA and theprotrusions RAP may enhance the rigidity of the back cover 1510 toprotect the back cover 1510 and the display panel 120 attached to theback cover 1510 from the external impacts.

Further, in the display device according to still another exemplaryembodiment of the present disclosure, even if external impacts areapplied to the left edge and the right edge of the back cover 1510, theprotrusions RAP may support the plurality of reinforcement areas RA sothat the back cover 1510 may be maintained flat without being bent.Therefore, in the display device according to another exemplaryembodiment of the present disclosure, the protrusions RAP may be furtherprovided in the plurality of reinforcement areas RA of the back cover1510 to enhance the rigidity at both edges of the back cover 1510.

FIG. 16 is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure. With theexception of a shape of protrusions RAP being different, otherconfigurations of the example back cover 1610 of FIG. 16 may besubstantially the same as the example back cover 1510 of FIGS. 15A and15B. Thus, a redundant description will be omitted.

As shown in FIG. 16, the plurality of protrusions RAP may extend in arow direction and may have a sine wave shape. That is, the protrusionsRAP may have a curved shape rather than a straight-line shape. Further,a distance AM between an uppermost portion and a lowermost portion ofthe plurality of protrusions RAP in a column direction may not exceedthe maximum width MW of the plurality of reinforcement areas RA, whichhas been described above with reference to FIG. 14. Here, the distanceAM between the uppermost portion and the lowermost portion of theprotrusions RAP may be defined as a width in the column directionbetween a maximum protruding point at the uppermost position and amaximum protruding point at the lowermost position.

Even though, in FIG. 16, the plurality of protrusions RAP is illustratedto have a sine wave shape and the plurality of reinforcement areas RA alinear shape, so long as the distance AM between the uppermost portionand the lowermost portion of the protrusions RAP does not exceed themaximum width MW of the reinforcement area RA, the shapes of theplurality of reinforcement areas RA and of the protrusions RAP may bemodified in various shapes and are not limited to the illustratedexample. For example, the protrusions RAP may have a zigzag pattern or apulse wave shape. Furthermore, the shape of the protrusions RAP may be aperiodic pattern or aperiodic pattern.

In the display device according to another exemplary embodiment of thepresent disclosure, the plurality of protrusions RAP having variousshapes may be disposed in the back cover 1610 to enhance the rigidity ofthe back cover 1610. Specifically, the plurality of reinforcement areasRA and the protrusions RAP protruding out of the rear surface of theback cover 1610 from the plurality of reinforcement areas RA may bedisposed in the second malleable area MA2 of the back cover 1610. Theplurality of protrusions RAP may extend in a row direction and may havea sine wave shape or another shape. In this case, the distance AMbetween the uppermost portion and the lowermost portion of theprotrusions RAP in the column direction may be within the maximum widthMW of the reinforcement area RA determined by the radius R of the roller851, the thickness t1 of the back cover 1610, the thickness t2 of thesecond adhesive layer AD2, and the compressibility “a” of the secondadhesive layer AD2. Therefore, when the back cover 1610 is wound, theplurality of protrusions RAP and the plurality of reinforcement areas RAmay enhance the rigidity of the back cover 1610 without interfering withthe display panel 120 to protect the back cover 1610 and the displaypanel 120 attached to the back cover 1610 from impacts from the outsideof the back cover 1610. Therefore, in the display device according toanother exemplary embodiment of the present disclosure, the plurality ofreinforcement areas RA and protrusions RAP of the back cover 1610 may bedesigned to have various shapes and may enhance the rigidity of the backcover 1610.

<Protection of Edge of Back Cover and Mitigation of Risk>

FIG. 17 is an enlarged cross-sectional view of a display unit of adisplay device according to still another exemplary embodiment of thepresent disclosure. With the exception of the back cover 1710 beingdifferent, other configurations of the example display unit DPb of FIG.17 may be substantially the same as the example display unit DPa ofFIGS. 8A to 9C. Thus, a redundant description will be omitted.

As illustrated in FIG. 17, a left edge and a right edge of the backcover 1710 may be bent. Specifically, the left edge and the right edgeof the back cover 1710 may be bent toward the display panel 120 so thatthe left edge and the right edge of the back cover 1710 may be disposedso as to face the respective side of the display panel 120. The leftedge and the right edge of the back cover 1710 may be bent to be spacedapart from the respective side of the display panel 120 and to face therespective side of the display panel 120. As the left edge and the rightedge of the back cover 1710 are bent, a leftmost portion EL and arightmost portion ER of the bent back cover 1710 may have a round shape.

In this case, even though the left edge and the right edge of the backcover 1710 are bent, the left edge and the right edge may be spacedapart from the display panel 120. Specifically, the left edge and theright edge of the back cover 1710 may be bent so as not to be in contactwith the substrate 121, the buffer layer 122, the pixel unit 123, theencapsulation layer 124, and the encapsulation substrate 125 of thedisplay panel 120.

Even though, in FIG. 17, the left edge and the right edge of the backcover 1710 are illustrated as not being in contact with the frontsurface of the back cover 1710, they are not limited to the illustratedexample. For example, the left edge and the right edge of the back cover1710 may be bent to be in contact with the front surface of the backcover 1710. Specifically, the left edge and the right edge of the backcover 1710 may be bent to be in contact with one surface of the backcover 1710 facing the display panel 120.

Since the back cover 1710 may be formed of a metal material or a plasticmaterial having a high rigidity, the left edge and the right edge of theback cover 1710 may be very sharp. Further, if the back cover 1710 isthick, much stress may be generated by winding and unwinding of thedisplay panel 120 and the back cover 1710. The back cover 1710 itselfmay undergo plastic deformation so that the back cover 1710 may beformed to have a very small thickness, e.g., approximately 200 μm.Therefore, a thin and sharp edge of the back cover 1710 may bevulnerable to external impacts to be easily deformed, posing a potentialrisk that the user may be injured by the sharp edge.

Therefore, in a display device according to still another exemplaryembodiment of the present disclosure, the left edge and the right edgeof the back cover 1710 may be bent to prevent or mitigate a sharp edge.Specifically, the left edge and the right edge of the back cover 1710may be bent so that the leftmost portion EL and the rightmost portion ERof the bent back cover 1710 have a round shape. Therefore, a potentialrisk of the user being injured by the leftmost portion EL or therightmost portion ER of the bent back cover 1710 may be prevented ormitigated.

Further, in the display device according to another exemplary embodimentof the present disclosure, the thickness of the leftmost portion EL andthe rightmost portion ER of the back cover 1710 may be larger than thatof other portions of the back cover 1710. Therefore, the rigidity in theleftmost portion EL and the rightmost portion ER of the bent back cover1710 may be enhanced. Further, even if the external force is applied tothe left and right of the back cover 1710, deformation of the back cover1710 may be minimized. Further, a sharp edge of the back cover 1710 maybe prevented or mitigated, and the rigidity of the back cover 1710 maybe enhanced by a process of bending the edges of the back cover 1710without incorporating an additional component.

<Suppression of Side Permeation Using Back Cover and Adhesive Layer>

FIGS. 18 to 20 are enlarged cross-sectional views of a display unit of adisplay device according to various exemplary embodiments of the presentdisclosure. FIG. 18 is an enlarged cross-sectional view of a displayunit DPc of a display device according to still another exemplaryembodiment of the present disclosure. FIG. 19 is an enlargedcross-sectional view of a display unit DPd of a display device accordingto yet another exemplary embodiment of the present disclosure. FIG. 20is an enlarged cross-sectional view of a display unit DPe of a displaydevice according to still another exemplary embodiment of the presentdisclosure. With the exception of the back covers 1810, 1910, and 2010being different and the third adhesive layer AD3 being added, otherconfigurations of the example display units DPc, DPd, and DPe of FIGS.18 to 20 may be substantially the same as the example display unit DPbof FIG. 17. Thus, a redundant description will be omitted.

As illustrated in FIGS. 18 to 20, the left edge and the right edge ofthe back covers 1810, 1910, and 2010 may be bent to be in contact withthe display panel 120. For example, as shown in FIG. 18, the left edgeand the right edge of the back cover 1810 may be bent to be in contactwith the rear surface of the display panel 120. That is, as illustratedin FIG, 18, the left edge and the right edge of the back cover 1810 maybe in contact with the rear surface of the buffer layer 122. However,embodiments not limited thereto, and the left edge and the right edge ofthe back cover 1810 may be bent to be in contact, for example, with therear surface of the substrate 121 of the display panel 120. Further, theleft edge and the right edge of the back cover 1810 may be in contactwith a rear surface of a plurality of insulating layers disposed betweenthe substrate 121 and the pixel unit 123 of the display panel 120, forexample, a rear surface of at least one of various insulating layers,such as the buffer layer 122, a gate insulating layer, an interlayerinsulating layer, a planarization layer, and a passivation layer.

Further, as shown in FIG. 19, the left edge and the right edge of theback cover 1910 may be bent to be in contact with the respective sidesof the display panel 120. That is, as illustrated in FIG. 19, the leftedge and the right edge of the back cover 1910 may be in contact withthe respective sides of the substrate 121 and the buffer layer 122.However, embodiments are not limited thereto, and the left edge and theright edge of the back cover 1910 may be bent to be in contact, forexample, with respective sides of any one of the substrate 121 and thebuffer layer 122. Further, the left edge and the right edge of the backcover 1910 may be in contact with sides of at least one of the pluralityof insulating layers disposed between the substrate 121 and the pixelunit 123 and the substrate 121.

Further, as shown in FIG. 20, the left edge and the right edge of theback cover 2010 may be bent to be in contact with the front surface ofthe display panel 120. That is, the left edge and the right edge of theback cover 2010 may be in contact with the front surface of thesubstrate 121. However, embodiments are not limited thereto, and if apolarizer or a protective film is disposed on the front surface of thesubstrate 121 of the display panel 120, the left edge and the right edgeof the back cover 2010 may be bent to be in contact with any of thecomponents disposed on the front surface of the substrate 121 of thedisplay panel 120.

As illustrated in FIGS. 18 to 20, a third adhesive layer AD3 may bedisposed in a space between the left edge and the right edge of the backcovers 1810, 1910, and 2010 and the display panel 120. The thirdadhesive layer AD3 may fill at least a portion of a space between theback covers 1810, 1910, and 2010 and the side of the display panel 120.Specifically, the third adhesive layer AD3 may fill at least a portionof a space between one surface of the back covers 1810, 1910, and 2010adjacent to the left edge and the right edge and the respective side ofthe display panel 120. For example, as shown in FIG. 18, the thirdadhesive layer AD3 may fill a space formed by the back cover 1810, thefirst adhesive layer AD1, the encapsulation substrate 125, the secondadhesive layer AD2, and the buffer layer 122. Further, as shown in FIG.19, the third adhesive layer AD3 may fill a space formed by the backcover 1910, the first adhesive layer AD1, the encapsulation substrate125, the second adhesive layer AD2, the buffer layer 122, and the sideof the substrate 121. Further, as shown in FIG. 20, the third adhesivelayer AD3 may fill a space formed by the back cover 2010, the firstadhesive layer AD1, the encapsulation substrate 125, the second adhesivelayer AD2, the buffer layer 122, and the respective side and therespective front surface of the substrate 121.

The third adhesive layer AD3 may fix the back covers 1810, 1910, and2010 and the display panel 120 to each other so that the left edge andthe right edge of the back covers 1810, 1910, and 2010 maintain acontact state with the display panel 120. The third adhesive layer AD3may be, for example, an epoxy non-conductive adhesive, but is notlimited thereto.

Further, the third adhesive layer AD3 may be a material having a softproperty. Therefore, even though an external impact is applied to thethird adhesive layer AD3 having a soft property, the third adhesivelayer AD3 may absorb or cushion the impact and protect the display panel120 and the back covers 1810, 1910, and 2010. The third adhesive layerAD3 may be a material having a low modulus and, for example, may be amaterial having a modulus of 0.05 MPa to 5 MPa, but is not limitedthereto.

In addition, the third adhesive layer AD3 may minimize moisture andoxygen permeating into the side of the display panel 120. As the thirdadhesive layer AD3 fills spaces to enclose the sides of the displaypanel 120, permeation paths of the moisture and oxygen at the side ofthe display panel 120 may increase. Accordingly, the third adhesivelayer AD3 may be disposed to protect the display panel 120 from themoisture and oxygen to improve the reliability of the display panel 120.

Further, the third adhesive layer AD3 may include an absorbent. Theabsorbent included in the third adhesive layer AD3 may be particleshaving hygroscopicity. The absorbent may minimize the permeation ofexternal moisture and oxygen into the display panel 120.

In the display device according to various exemplary embodiments of thepresent disclosure, the left edge and the right edge of the back covers1810, 1910, and 2010 may be bent to prevent or mitigate sharp edges.Specifically, the left edge and the right edge of the back covers 1810,1910, and 2010 may otherwise be very thin and sharp to be dangerous, andbe vulnerable to external impacts to be easily deformed. The left edgeand the right edge of the back covers 1810, 1910, and 2010 may be bentto be in contact with the display panel 120 so that the leftmost portionEL and the rightmost portion ER of the back covers 1810, 1910, and 2010may have a round shape. For example, as shown in FIG. 18, the left edgeand the right edge of the back cover 1810 may be bent to be in contactwith the rear surface of the display panel 120. As shown in FIG. 19, theleft edge and the right edge of the back cover 1910 may be bent to be incontact with the respective side of the display panel 120. As shown inFIG. 20, the left edge and the right edge of the back cover 2010 may bebent to be in contact with the front surface of the substrate 121 of thedisplay panel 120. The left edge and the right edge of the back covers1810, 1910, and 2010 of FIGS. 18 to 20 may be bent to be in contact withthe display panel 120 so that the leftmost portion EL and the rightmostportion ER of the back covers 1810, 1910, and 2010 may have a roundshape. Therefore, in the display device according to various exemplaryembodiments of the present disclosure, the left edge and the right edgeof the back covers 1810, 1910, and 2010 may be bent to allow theleftmost portion and the rightmost portion of the back covers 1810,1910, and 2010 to have a round shape. Therefore, sharp edges may beprevented, and a potential injury of the user caused by a sharp edge maybe prevented or minimized.

Further, in the display device according to various exemplaryembodiments of the present disclosure, the third adhesive layer AD3 mayfill the space between the back covers 1810, 1910, and 2010 and therespective sides of the display panel 120 to enhance a side rigidity ofthe display units DPc, DPd, and DPe. Specifically, the third adhesivelayer AD3 may be formed of a material having a soft property having alow modulus to absorb and cushion impacts. The third adhesive layer AD3may fill the space between the back covers 1810, 1910, and 2010 and therespective sides of the display panel 120 to absorb and cushion theimpacts at the side of the display units DPc, DPd, and DPe. For example,as shown in FIG. 18, the left edge and the right edge of the back cover1810 may be bent to be in contact with the rear surface of the displaypanel 120, and the third adhesive layer AD3 may fill the space betweenthe back cover 1810 and the rear surface of the display panel 120. Asshown in FIG. 19, the left edge and the right edge of the back cover1910 may be bent to be in contact with the respective sides of thedisplay panel 120, and the third adhesive layer AD3 may fill the spacebetween the back cover 1910 and the rear surface and the respectivesides of the display panel 120. Finally, as shown in FIG. 20, the leftedge and the right edge of the back cover 2010 may be bent to be incontact with the front surface of the display panel 120, and the thirdadhesive layer AD3 may fill the space between the back cover 2010, andthe rear surface, the respective sides, and the front surface of thedisplay panel 120. Therefore, in the display device according to variousexemplary embodiments of the present disclosure, the third adhesivelayer AD3 having a soft property may fill the space between the backcovers 1810, 1910, and 2010 and the display panel 120. Therefore, thethird adhesive layer AD3 may cushion the external impacts applied to theback covers 1810, 1910, and 2010 of the display units DPc, DPd, and DPeand the display panel 120 and minimize a potential damage to the displayunits DPc, DPd, and DPe.

Moreover, in the display device according to various exemplaryembodiments of the present disclosure, the third adhesive layer AD3filling the space between the back covers 1810, 1910, and 2010 and thedisplay panel 120 may minimize the permeation of the moisture and oxygeninto the side of the display panel 120 to improve the reliability of thedisplay device. Specifically, the left edge and the right edge of theback covers 1810, 1901, and 2010 may be bent to be in contact with thedisplay panel 120, and the third adhesive layer AD3 may fill the spacebetween the back covers 1810, 1910, and 2010 and the display panel 120.Further, the third adhesive layer AD3 may fill the space so as toenclose the side of the display panel 120 and increase the number ofpermeation paths of the moisture and oxygen into the sides of thedisplay panel 120, thereby preventing or minimizing the permeation ofmoisture and oxygen into the sides of the display panel 120. Forexample, as shown in FIGS. 18 to 20, the left edge and the right edge ofthe back covers 1810, 1910, and 2010 may be bent to be in contact withthe rear surface, the side, or the front surface of the display panel120, and the back covers 1810, 1910, and 2010 may be disposed to enclosethe respective sides of the pixel unit 123 of the display panel 120.Further, the third adhesive layer AD3 may fill the space between therespective side of the pixel unit 123 of the display panel 120 and theback covers 1810, 1910, and 2010 so that the permeation of the moistureand oxygen into the side of the pixel unit 123 may be minimized.Further, the third adhesive layer AD3 may further include an absorbenthaving hygroscopicity so that the moisture and oxygen permeationsuppression effect may be improved by the absorbent. Therefore, in thedisplay device according to various exemplary embodiments of the presentdisclosure, the left edge and the right edge of the back covers 1810,1910, and 2010 may be bent to fill the space between the back covers1810, 1910, and 2010 and the respective side of the display panel 120with the third adhesive layer AD3. Therefore, the permeation of moistureand oxygen into the side of the display panel 120 may be minimized.

<Enhancement of Suppression of Permeation Using Auxiliary EncapsulationLayer>

FIG. 21 is a plan view of a display unit of a display device accordingto still another exemplary embodiment of the present disclosure. Withthe exception of an auxiliary encapsulation layer 124 a being added,other configurations of the example display unit DPf of FIG. 21 may besubstantially the same as those of the example display unit DPd of FIG.19. Thus, a redundant description will be omitted.

As illustrated in FIG. 21, the auxiliary encapsulation layer 124 a maybe disposed on the back cover 810 to cover an upper edge of the displaypanel 120. Specifically, the auxiliary encapsulation layer 124 a maycover a part of a front surface of the back cover 810 adjacent to anupper edge of the display panel 120 and a part of a front surface of thedisplay panel 120 adjacent to the upper edge of the display panel 120 soas to cover the upper edge of the display panel 120.

The auxiliary encapsulation layer 124 a may be an epoxy or acrylicnon-conductive material, but is not limited thereto. Further, theauxiliary encapsulation layer 124 a may further include an absorbent.The absorbent included in the auxiliary encapsulation layer 124 a may beparticles having hygroscopicity. The absorbent may minimize thepermeation of external moisture and oxygen into the display panel 120.

In the display device according to still another exemplary embodiment ofthe present disclosure, the auxiliary encapsulation layer 124 a mayfurther be provided to cover the upper edge of the display panel 120disposed on the back cover 810 to protect the display panel 120 from theexternal moisture and oxygen. The left edge and the right edge of thedisplay panel 120 disposed on the back cover 810 may be protected by thethird adhesive layer AD3 but, without the auxiliary encapsulation layer124 a, the upper edge of the display panel 120 may be directly exposedto the outside so that oxygen and moisture may permeate thereinto. Inthis case, the auxiliary encapsulation layer 124 a may be disposed tocover the upper edge of the display panel 120 to seal the upper side ofthe display panel 120. That is, the auxiliary encapsulation layer 124 amay be disposed so as to enclose the upper side of the display panel 120to block a path or to increase a number of paths through which moistureand oxygen permeate into the upper side of the display panel 120,thereby minimizing the permeation of the moisture and oxygen into thedisplay panel 120. Further, the auxiliary encapsulation layer 124 a mayfurther include an absorbent which may absorb the moisture and oxygen.Therefore, in the display device according to still another exemplaryembodiment of the present disclosure, the auxiliary encapsulation layer124 a may further be provided to cover an upper edge among edges of thedisplay panel 120 to minimize the permeation of the moisture and oxygeninto the display panel 120, thereby improving the reliability of thedisplay panel 120.

Even though, in FIG. 21, the auxiliary encapsulation layer 124 a isillustrated as being disposed to cover the upper edge of the displaypanel 120, it is not limited thereto. For example, the auxiliaryencapsulation layer 124 a may be disposed, additionally oralternatively, to cover a lower edge of the display panel 120.

<Guide of Winding and Unwinding of Display Device>

FIG. 22 is a plan view of a display unit of a display device accordingto still another exemplary embodiment of the present disclosure. FIG. 23is a cross-sectional view of a display unit of FIG. 22 in a state ofbeing wound around a roller. Specifically, FIG. 23 is a frontcross-sectional view of a back cover 2210, a display panel 120, and aroller 151 in a state in which the back cover 2210 and the display panel120 are wound around the roller 151. With the exception of the backcover 2210 being different, other configurations of the example displayunit DPg of FIGS. 22 and 23 may be substantially the same as the exampledisplay unit DPb of FIG. 17. Thus, a redundant description will beomitted. For the convenience of description, in FIG. 22, only the backcover 2210 and the display panel 120 among the components of the displayunit DPg are schematically illustrated.

As shown in FIG. 22, the back cover 2210 may have a trapezoidal shape. Alength of a lower edge of the back cover 2210 is longer than a length ofan upper edge of the back cover 2210. That is, a left edge and a rightedge of the back cover 2210 may be inclined with respect to the loweredge of the back cover 2210. In other words, the left edge and the rightedge of the back cover 2210 may be inclined with respect to the upperedge of the back cover 2210. Therefore, a width between the left edgeand the right edge of the back cover 2210 in a row direction in one partof the back cover 2210 may be different from a width between the leftedge and the right edge of the back cover 2210 in another part of theback cover 2210. For example, a width between the left edge and theright edge of the back cover 2210 in an upper end of the back cover 2210may be smaller than a width between the left edge and the right edge ofthe back cover 2210 in the row direction in a lower end of the backcover 2210. As described above, the back cover 2210 may have atrapezoidal shape which becomes narrower toward the upper end. However,the back cover 2210 is not limited thereto, and various shapes in whichthe width is increased from the lower end to the upper end may beapplied to the back cover 2210.

As shown in FIG. 23, the left edge and the right edge of the back cover2210 may be bent to be in contact with the front surface of the backcover 2210. Specifically, the left edge and the right edge of the backcover 2210 may be bent to be in contact with the front surface of theback cover 2210 to which the display panel 120 is attached. Therefore,an overall thickness of the leftmost portion EL and the rightmostportion ER of the bent back cover 2210, respectively, may be larger thana base thickness of the back cover 2210 in the remaining portions. Theoverall respective thickness of the leftmost portion EL and therightmost portion ER of the bent back cover 2210 may be larger than asum of a base thickness of the back cover 2210 and a thickness of thedisplay panel 120. Further, the left edge and the right edge of the backcover 2210 may be bent to prevent or mitigate thin and sharp left andright edges of the back cover 2210.

With the back cover 2210 formed to have a trapezoidal shape, when theback cover 2210 is wound, the leftmost portion EL and the rightmostportion ER of the bent back cover 2210 may not interfere with otherparts of the back cover 2210 being wound. Further, the leftmost portionEL and the rightmost portion ER of the bent back cover 2210 may guidethe winding of the back cover 2210.

For the purpose of detailed description, it is assumed that the roller151 makes three rotations to completely wind the back cover 2210 aroundthe roller 151 although embodiments are not limited to this number ofrotations. Under this assumption, when the roller 151 makes a firstrotation, a lower end area of the back cover 2210 may be wound aroundthe roller 151. When the roller 151 makes a second rotation, a centerarea of the back cover 2210 may be wound around the roller 151. When theroller 151 makes a third rotation, an upper end area of the back cover2210 may be wound around the roller 151. The number of rotations of theroller 151 required to wind the back cover 2210 completely around theroller 151 may vary depending on the design, and the lengths of thelower edge and the upper edge of the back cover 2210 may also varydepending on the number of rotations of the roller 151, but is notlimited thereto.

First, the leftmost portion EL of the bent back cover 2210 may include afirst left portion EL1, a second left portion EL2, and a third leftportion EL3. The rightmost portion ER of the bent back cover 2210 mayinclude a first right portion ER1, a second right portion ER2, and athird right portion ER3.

The first left portion EL1 and the first right portion ER1 mayrespectively be a leftmost portion and a rightmost portion in a lowerend of the back cover 2210 and, as illustrated in FIG. 23, may form alayer disposed closest to the roller 151 when the back cover 2210 iswound around the roller 151. The second left portion EL2 and the secondright portion ER2 may respectively be a leftmost portion and a rightmostportion in the center portion of the back cover 2210 and, as illustratedin FIG. 23, may form a layer second closest to the roller 151 when theback cover 2210 is wound around the roller 151. The third left portionEL3 and the third right portion ER3 may respectively be a leftmostportion and a rightmost portion in an upper end of the back cover 2210and, as illustrated in FIG. 23, may form a layer farthest away from theroller 151 when the back cover 2210 is wound around the roller 151.

As illustrated together in FIG. 23, the first left portion EL1 and thefirst right portion ER1 may be first wound around the roller 151.Therefore, the first left portion EL1 and the first right portion ER1may be in direct contact with an outer circumferential surface of theroller 151.

In a state in which the first left portion EL1 and the first rightportion ER1 have been wound around the roller 151, the second leftportion EL2 and the second right portion ER2 may be wound around theroller 151 with the first left portion EL1 and the first right portionER1 wound thereon. However, the second left portion EL2 and the secondright portion ER2 may be disposed so as not to overlap the first leftportion EL1 and the first right portion ER1, but to overlap a middlearea of the back cover 2210 between the first left portion EL1 and thefirst right portion ER1.

The second left portion EL2 and the second right portion ER2 may bedisposed closer to the lateral center of the roller 151 than the firstleft portion EL1 and the first right portion ER1. Specifically, as shownin FIG. 22, the width between the left edge and the right edge of theback cover 2210 in the row direction becomes smaller from the lower endto the upper end. Therefore, a width of a center portion of the backcover 2210 in which the second left portion EL2 and the second rightportion ER2 are disposed may be smaller than a width of the lower endportion of the back cover 2210 in which the first left portion EL1 andthe first right portion ER1 are disposed. Therefore, the width betweenthe second left portion EL2 and the second right portion ER2 in the rowdirection may be smaller than a width between the first left portion EL1and the first right portion ER1. Accordingly, the second left portionEL2 and the second right portion ER2 may be disposed within a lateralspace between the first left portion EL1 and the first right portionER1.

In a state in which the first left portion EL1, the first right portionER1, the second left portion EL2, and the second right portion ER2 havebeen wound around the roller 151, the third left portion EL3 and thethird right portion ER3 may be wound around the roller 151 with thefirst left portion EL1, the first right portion ER1, the second leftportion EL2, and the second right portion ER2 wound thereon. The thirdleft portion EL3 and the third right portion ER3 may be disposed so asnot to overlap the second left portion EL2 and the second right portionER2, but may be disposed to overlap a middle area of the back cover 2210between the second left portion EL2 and the second right portion ER2.

The third left portion EL3 and the third right portion ER3 may bedisposed to be closer to the lateral center of the roller 151 than thesecond left portion EL2 and the second right portion ER2. Specifically,as shown in FIG. 22, a width in the row direction of the upper endportion of the back cover 2210 in which the third left portion EL3 andthe third right portion ER3 are disposed may be smaller than a width ofthe center portion of the back cover 2210 in which the second leftportion EL2 and the second right portion ER2 are disposed. Therefore,the width between third left portion EL3 and the third right portion ER3in the row direction may be smaller than a width between the second leftportion EL2 and the second right portion ER2. Therefore, the third leftportion EL3 and the third right portion ER3 may be disposed within alateral space betwen the second left portion EL2 and the second rightportion ER2.

In a state in which the back cover 2210 is wound around the roller 151,the uppermost portions of the first left portion EL1 and the first rightportion ER1 are disposed to protrude beyond the display panel 120. In astate in which the back cover 2210 is wound around the roller 151, theuppermost portions of the first left portion EL1 and the first rightportion ER1 may be disposed to protrude beyond the the lower surfaces ofthe second left portion EL2 and the second right portion ER2,respectively. Therefore, when the back cover 2210 is wound, the secondleft portion EL2 and the second right portion ER2 do not move outside ofthe first left portion EL1 and the first right portion ER1.

Further, the protruding sides of the first left portion EL1 and thefirst right portion ER1 may be in contact with sides of the second leftportion EL2 and the second right portion ER2, respectively. Therefore,when the back cover 2210 is wound around the roller 151, the second leftportion EL2 and the second right portion ER2 may be guided to bepositioned between the first left portion EL1 and the first rightportion ER1 while being in contact with the sides of the first leftportion EL1 and the first right portion ER1. Therefore, when the backcover 2210 is wound, the first left portion EL1 and the first rightportion ER1 which protrude toward the front surface of the back cover2210 may guide the center portion of the back cover 2210 in which thesecond left portion EL2 and the second right portion ER2 are disposed tobe stably wound around the roller 151.

Similarly, in a state in which the back cover 2210 is wound around theroller 151, the uppermost portions of the second left portion EL2 andthe second right portion ER2 may be disposed to protrude beyond thelower surfaces of the third left portion EL3 and the third right portionER3, respectively. Therefore, when the back cover 2210 is wound, thethird left portion EL3 and the third right portion ER3 may be disposedonly between the second left portion EL2 and the second right portionER2, and do not move outside of the second left portion EL2 and thesecond right portion ER2.

Further, the protruding sides of the second left portion EL2 and thesecond right portion ER2 may be in contact with sides of the third leftportion EL3 and the third right portion ER3, respectively. Therefore,when the back cover 2210 is wound around the roller 151, the third leftportion EL3 and the third right portion ER3 may be guided to bepositioned between the second left portion EL2 and the second rightportion ER2 while being in contact with the sides of the second leftportion EL2 and the second right portion ER2. Therefore, when the backcover 2210 is wound, the second left portion EL2 and the second rightportion ER2 which protrude toward the front surface of the back cover2210 may guide the upper end portion of the back cover 2210 in which thethird left portion EL3 and the third right portion ER3 are disposed tobe stably wound around the roller 151.

If the winding of the back cover 2210 is guided, the sides of the firstleft portion EL1 and the first right portion ER1 and the sides of thesecond left portion EL2 and the second right portion ER2 may be spacedapart from each other without being in contact with each other. Further,the sides of the second left portion EL2 and the second right portionER2 and the sides of the third left portion EL3 and the third rightportion ER3 may be spaced apart from each other without being in contactwith each other. However, embodiments are not limited to the abovespecific examples.

In FIGS. 22 and 23, an entire planar shape of the back cover 2210 isillustrated to have a trapezoidal shape as an example. However, only apartial area of the back cover 2210 which is wound around or unwoundfrom the roller 151 may be formed to have a trapezoidal shape, andembodiments are not limited thereto. For example, if only the secondsupport area PA2, the third malleable area MA3, the fourth support areaPA4, and the second malleable area MA2 of the back cover 2210 are to bewound around or unwound from the roller 151, and the first support areaPA1, the first malleable area MA1, and the third support area PA3 of theback cover 2210 are to maintain a flat state, the second support areaPA2, the third malleable area MA3, the fourth support area PA4, and thesecond malleable area MA2 of the back cover 2210 may be formed to have atrapezoidal shape. Further, the first support area PA1, the firstmalleable area MA1, and the third support area PA3 may be formed to havea rectangular shape in which the width between the left edge and theright edge in the row direction is constant.

In the display device according to still another exemplary embodiment ofthe present disclosure, the back cover 2210 may be formed to have atrapezoidal shape in which the width in the row direction becomesnarrower from the lower end to the upper end. This may minimizeinterference between the rear surface of the back cover 2210, and theleftmost portion EL and the rightmost portion ER protruding toward thefront surface of the back cover as the left edge and the right edge arebent toward the front surface of the back cover 2210, when the backcover 2210 is wound. Specifically, the left edge and the right edge ofthe back cover 2210 may be bent toward a surface of the back cover 2210to which the display panel 120 is attached, and may protrude from thatsurface. Further, the back cover 2210 may be formed to have atrapezoidal shape in which a length of the lower edge in the rowdirection is longer than a length of the upper edge. Therefore, at thetime of winding, the larger the number of rotations of the roller 151,the smaller the width between the left edge and the right edge of theback cover 2210 being wound around the roller 151. Therefore, eventhough another part of the back cover 2210 is further wound on a portionof the back cover 2210 having the leftmost portion EL and the rightmostportion ER bent toward the front surface of the back cover 2210 toprotrude, the width of the back cover 2210 may be gradually narrowed toaccommodate another part of the back cover 2210 being wound to bepositioned between the protruding leftmost portion EL and rightmostportion ER. Therefore, in the display device according to still anotherexemplary embodiment of the present disclosure, the back cover 2210 maybe formed to have a trapezoidal shape so that the rear surface of theback cover 2210, and the leftmost portion EL and the rightmost portionER protruding toward the front surface of the back cover 2210 do notinterfere with each other.

Further, in the display device according to another exemplary embodimentof the present disclosure, the protruding leftmost portion EL andrightmost portion ER of the back cover 2210 may guide the winding andunwinding of the back cover 2210. For example, when the roller 151 makesa first rotation, the first left portion EL1 and the first right portionER1 of the back cover 2210 wound around the roller 151 may be disposedfarthest away from the lateral center of the roller 151. Next, when theroller 151 makes a second rotation, the second left portion EL2 and thesecond right portion ER2 of the back cover 2210 wound around the roller151 may be disposed between the first left portion EL1 and the firstright portion ER1, without moving laterally outside the first leftportion EL1 or the first right portion ER1. When the roller 151 makes athird rotation, the third left portion EL3 and the third right portionER3 of the back cover 2210 wound around the roller 151 may be disposedbetween the second left portion EL2 and the second right portion ER2,without moving laterally outside the second left portion EL2 or thesecond right portion ER2. As described above, the left edge and theright edge of the back cover 2210 wound around the roller 151 may eachbe wound so as not to overlap itself In this case, the first leftportion EL1 and the first right portion ER1 protrude beyond the lowersurfaces of the second left portion EL2 and the second right portion ER2to guide the second left portion EL2 and the second right portion ER2 tobe positioned between the first left portion EL1 and the first rightportion ER1 without laterally moving outside the space between the firstleft portion EL1 and the first right portion ER1. Similarly, the secondleft portion EL2 and the second right portion ER2 protrude beyond thelower surfaces of the third left portion EL3 and the third right portionER3 to guide the third left portion EL3 and the third right portion ER3to positioned between the second left portion EL2 and the second rightportion ER2. Therefore, in the display device according to still anotherexemplary embodiment of the present disclosure, the leftmost portion ELand the rightmost portion ER protruding toward the front surface of theback cover 2210 may guide the back cover 2210 to be wound around andunwound from the roller 151, and prevent or suppress the back cover 2210from deviating from the designed position.

Moreover, in a display device according to still another exemplaryembodiment of the present disclosure, the left edge and the right edgeof the back cover 2210 may be bent to prevent or minimize sharp edges.Specifically, the back cover 2210 may be formed of a material which isvery thin and has a high rigidity, and the left edge and the right edgeof the back cover 2210 may otherwise become very sharp. Therefore, theleft edge and the right edge of the back cover 2210 may be bent towardthe front surface of the back cover 2210, that is, a surface of the backcover 2210 to which the display panel 120 is attached. Since theleftmost portion EL and the rightmost portion ER of the back cover 2210in which the left edge and the right edge are bent may have a roundshape to prevent or minimize sharp edges of the back cover 2210 toprevent or minimize the risk of injury to the user.

FIG. 24 is a plan view of a display unit of a display device accordingto still another exemplary embodiment of the present disclosure. FIG. 25is a cross-sectional view of a display unit of FIG. 24 which is woundaround a roller. With the exception of a back cover 2410 being differentand guide units GPL and GPR being added, other configurations of anexample display unit DPh of FIGS. 24 and 25 may be substantially thesame as the example display unit DPg of FIGS. 22 and 23. Thus, aredundant description will be omitted.

As illustrated in FIG. 24, a left guide unit GPL may be disposed at aleft edge of the back cover 2410, and a right guide unit GPR may bedisposed at a right edge of the back cover 2410. The left guide unit GPLmay be disposed to enclose the left edge of the back cover 2410. Theright guide unit GPR may be disposed to enclose the right edge of theback cover 2410. The left guide unit GPL and the right guide unit GPRmay be disposed to be in contact with the left edge and the right edgeof the back cover 2410, but are not limited to this exampleconfiguration.

The left guide unit GPL may include a first left guide unit GPL1, asecond left guide unit GPL2, and a third left guide unit GPL3. The firstto the third left guide units GPL1, GPL2, GPL3 may be three portions ofa single contiguous left guide unit GPL, but are not limited thereo. Theright guide unit GPR may include a first right guide unit GPR1, a secondright guide unit GPR2, and a third right guide unit GPR3. The first tothe third right guide units GPR1, GPR2, GPR3 may be three portions of asingle contiguous right guide unit GPR, but are not limited thereo.

The first left guide unit GPL1 and the first right guide unit GPR1 maybe disposed to enclose a first left portion EL1 and a first rightportion ER1, respectively, at a lower end portion of the back cover2410. The second left guide unit GPL2 and the second right guide unitGPR2 may be disposed to enclose a second left portion EL2 and a secondright portion ER2, respectively, in a center portion of the back cover2410. The third left guide unit GPL3 and the third right guide unit GPR3may be disposed to enclose a third left portion EL3 and a third rightportion ER3, respectively, at an upper end portion of the back cover2410.

In addition, the left guide unit GPL and the right guide unit GPR may beformed of a material having a flexibility to be wound around the roller151 together with the back cover 2410. For example, the left guide unitGPL and the right guide unit GPR may be formed of polymer or rubber, butare not limited thereto.

Further, the left guide unit GPL and the right guide unit GPR mayenclose the thin and possibly sharp left edge and right edge of the backcover 2410. At least a part of outer surfaces of the left guide unit GPLand the right guide unit GPR may be formed in a shape of a gentle curve.Therefore, sharp edges may be prevented or minimized in the back cover2410.

As illustrated in FIG. 25, lower surfaces of the left guide unit GPL andthe right guide unit GPR may be disposed on the same plane as the rearsurface of the back cover 2410. That is, the lower surfaces of the leftguide unit GPL and the right guide unit GPR may be wound while being inclose contact with the surface of the roller 151 without forming a stepwith the rear surface of the back cover 2410.

The thickness of the left guide unit GPL and the right guide unit GPRmay be larger than a sum of the thicknesses of the back cover 2410 andthe display panel 120. For example, a first height X from the rearsurface of the back cover 2410, which also serves as the lower surfaceof the left guide unit GPL, to an upper end of the left guide unit GPLis larger than a second height Y from the rear surface of the back cover2410 to the front surface of the display panel 120. Further, a firstheight X from the rear surface of the back cover 2410, which also servesas the lower surface of the right guide unit GPR, to an upper end of theright guide unit GPR is larger than a second height Y from the rearsurface of the back cover 2410 to the front surface of the display panel120.

The first height X, which is the thickness of the left guide unit GPL orthe right guide unit GPR, may be equal to or smaller than twice thesecond height Y, which is the combined thicknesses of the back cover2410 and the display panel 120. For example, the second height Y, whichis the combined thicknesses of the back cover 2410 and the display panel120, and the first height X which is the thickness of the left guideunit GPL or the right guide unit GPR may satisfy the following Equation2:

Y<X≤Y×2   [Equation 2]

Therefore, the thickness of each of the left guide unit GPL and theright guide unit GPR may be larger than the combined thicknesses of theback cover 2410 and the display panel 120, but may be equal to orsmaller than twice the combined thicknesses of the back cover 2410 andthe display panel 120.

The first left guide unit GPL1 and the first right guide unit GPR1 maybe first wound around the roller 151. Specifically, a lower edge of theback cover 2410 may be fastened with the roller 151, and the left edgeand the right edge of the lower end portion of the back cover 2410 maybe first wound around the roller 151. Therefore, the first left guideunit GPL1 and the first right guide unit GPR1 which enclose the leftedge and the right edge of the lower end portion of the back cover 2410may also first wound around the roller 151 to be in contact with theouter circumferential surface of the roller 151.

With the first left guide unit GPL1 and the first right guide unit GPR1in a state of being wound around the roller 151, the second left guideunit GPL2 and the second right guide unit GPR2 may be wound on a lowerend portion of the back cover 2410 between the first left guide unitGPL1 and the first right guide unit GPR1. In this case, the second leftguide unit GPL2 and the second right guide unit GPR2 may be disposed notto overlap the first left guide unit GPL1 and the first right guide unitGPR1, but to overlap a lower end portion of the back cover 2410 betweenthe first left guide unit GPL1 and the first right guide unit GPR1.

The second left guide unit GPL2 and the second right guide unit GPR2 maybe disposed to be closer to the lateral center of the roller 151 thanthe first left guide unit GPL1 and the first right guide unit GPR1.Specifically, the back cover 2410 may have trapezoidal shape in which awidth becomes narrower from the lower end to the upper end. Therefore,the width between the first left guide unit GPL1 and the first rightguide unit GPR1 which enclose the left edge and the right edge in alower end area of the back cover 2410 may be larger than the widthbetween the second left guide unit GPL2 and the second right guide unitGPR2 which enclose the left edge and the right edge in a center area ofthe back cover 2410. Therefore, the second left guide unit GPL2 and thesecond right guide unit GPR2 may be disposed to be closer to the lateralcenter of the back cover 2410 than the first left guide unit GPL1 andthe first right guide unit GPR1.

With the first left guide unit GPL1 and the first right guide unit GPR1,the second left guide unit GPL2, and the second right guide unit GPR2 ina state of being wound around the roller 151, the third left guide unitGPL3 and the third right guide unit GPR3 may be wound on the centerportion of the back cover 2410 bewteen the second left guide unit GPL2and the second right guide unit GPR2. Further, the third left guide unitGPL3 and the third right guide unit GPR3 may be disposed not to overlapthe second left guide unit GPL2 and the second right guide unit GPR2,but to overlap the center portion of the back cover 2410 between thesecond left guide unit GPL2 and the second right guide unit GPR2.

The third left guide unit GPL3 and the third right guide unit GPR3 maybe disposed to be closer to the lateral center of the roller 151 thanthe second left guide unit GPL2 and the second right guide unit GPR2.Specifically, a width of the upper end portion of the back cover 2410 inwhich the third left guide unit GPL3 and the third right guide unit GPR3are disposed may be smaller than a width of the center portion of theback cover 2410 in which the second left guide unit GPL2 and the secondright guide unit GPR2. Therefore, the third left guide unit GPL3 and thethird right guide unit GPR3 may be disposed to be closer to the lateralcenter of the back cover 2410 than the second left guide unit GPL2 andthe second right guide unit GPR2.

When the back cover 2410 is wound around the roller 151, the uppermostportions of the first left guide unit GPL1 and the first right guideunit GPR1 protrude from the outer circumferential surface of the roller151 beyond the respective lower surfaces of the second left guide unitGPL2 and the second right guide unit GPR2, respectively. Therefore, whenthe back cover 2410 is wound, the second left guide unit GPL2 and thesecond right guide unit GPR2 may be disposed between the first leftguide unit GPL1 and the first right guide unit GPR1, without movinglaterally outside the first left guide unit GPL1 or the first rightguide unit GPR1.

Further, the protruding sides of the first left guide unit GPL1 and thefirst right guide unit GPR1 may be in contact with outer sides of thesecond left guide unit GPL2 and the second right guide unit GPR2,respectively. Therefore, when the back cover 2410 is wound around theroller 151, the second left guide unit GPL2 and the second right guideunit GPR2 may be guided to be disposed between the first left guide unitGPL1 and the first right guide unit GPR1 while being in contact with therespective inner sides of the first left guide unit GPL1 and the firstright guide unit GPR1. Therefore, when the back cover 2410 is wound, thefirst left guide unit GPL1 and the first right guide unit GPR1 whichprotrude toward the front surface of the back cover 2410 may guide thecenter portion of the back cover 2410 in which the second left guideunit GPL2 and the second right guide unit GPR2 are disposed to be stablywound around the roller 151.

Similarly, in a state in which the back cover 2410 is wound around theroller 151, the uppermost portions of the second left guide unit GPL2and the second right guide unit GPR2 may protrude beyond the lowersurfaces of the third left guide unit GPL3 and the third right guideunit GPR3, respectively. Therefore, when the back cover 2410 is wound,the third left guide unit GPL3 and the third right guide unit GPR3 maybe disposed between the second left guide unit GPL2 and the second rightguide unit GPR2, without moving laterally outside of the second leftguide unit GPL2 or the second right guide unit GPR2.

Further, the protruding sides of the second left guide unit GPL2 and thesecond right guide unit GPR2 may be in contact with outer sides of thethird left guide unit GPL3 and the third right guide unit GPR3,respectively. Therefore, when the back cover 2410 is wound around theroller 151, the third left guide unit GPL3 and the third right guideunit GPR3 may be guided to be disposed between the second left guideunit GPL2 and the second right guide unit GPR2 while being in contactwith the inner sides of the second left guide unit GPL2 and the secondright guide unit GPR2, respectively. Therefore, when the back cover 2410is wound, the second left guide unit GPL2 and the second right guideunit GPR2 which protrude toward the front surface of the back cover 2410may guide the upper end portion of the back cover 2410 in which thethird left guide unit GPL3 and the third right guide unit GPR3 aredisposed to be stably wound around the roller 151.

In the display device according to still another exemplary embodiment ofthe present disclosure, a left guide unit GPL and a right guide unit GPRmay be provided to enclose the thin and possibly sharp left edge andright edge of the back cover 2410, respectively. Otherwise, there is arisk that users or operators of the display device may be injured by thethin and sharp edge of the back cover 2410. Further, the thin back cover2410 may be vulnerable to impacts from the outside so that the backcover 2410 may be deformed. In this case, the left guide unit GPL andthe right guide unit GPR which enclose the thin and sharp edges of theback cover 2410 may be formed to have a gentle curved surface, may beformed of a material which is more flexible than the back cover 2410,and may be formed to be thicker than the back cover 2410. Therefore, itis possible to prevent or mitigate the thin and sharp edges of the backcover 2410. Further, the left guide unit GPL and the right guide unitGPR may be thicker than the back cover 2410 and the display panel 120combined so that the rigidity of the left edge and the right edge of theback cover 2410 may be enhanced. Therefore, even if the external forceis applied to the side of the back cover 2410, the deformation of theback cover 2410 may be minimized.

Further, in the display device according to still another exemplaryembodiment of the present disclosure, since the back cover 2410 isformed to have a trapezoidal shape, the left guide unit GPL (including,e.g., GPL1, GPL2, and GPL3) and the right guide unit GPR (including,e.g., GPR1, GPR2, and GPR3) which protrude toward the front surface ofthe back cover 2410 may be wound around the roller 151 withoutinterfering with each other. The back cover 2410 may have a trapezoidalshape in which a length of a lower edge in the row direction is largerthan a length of an upper edge in the row direction. Specifically, theback cover 2410 may have a trapezoidal shape in which a width becomesnarrower from the lower end to the upper end. In this case, the loweredge of the back cover 2410 may be fastened with the roller 151 to bewound around the roller 151 from the lower end of the back cover 2410.Therefore, the first left guide unit GPL1 and the first right guide unitGPR1 may be first wound around the roller 151, and then the second leftguide unit GPL2 and the second right guide unit GPR2 may be wound.Further, the width between the first left guide unit GPL1 and the firstright guide unit GPR1 is larger than the width between the second leftguide unit GPL2 and the second right guide unit GPR2. Therefore, thefirst left guide unit GPL1 and the first right guide unit GPR1 may notoverlap the second left guide unit GPL2 and the second right guide unitGPR2. Next, after the second left guide unit GPL2 and the second rightguide unit GPR2 are wound, the third left guide unit GPL3 and the thirdright guide unit GPR3 may be wound. Further, the width between thesecond left guide unit GPL2 and the second right guide unit GPR2 may belarger than the width between the third left guide unit GPL3 and thethird right guide unit GPR3. Therefore, the second left guide unit GPL2and the second right guide unit GPR2 may not overlap the third leftguide unit GPL3 and the third right guide unit GPR3. Therefore, in thedisplay device according to still another exemplary embodiment of thepresent disclosure, when the back cover 2410 is wound around the roller151, even if another part of the back cover 2410 is further wound withthe left guide unit GPL (including, e.g., GPL1, GPL2, and GPL3) and theright guide unit GPR (including, e.g., GPR1, GPR2, and GPR3) protrudingtoward the front surface of the back cover 2410, the width between theleft guide unit GPL and the right guide unit GPR becomes smaller fromthe lower end to the upper end of the back cover 2410. Therefore, therear surface of the back cover 2410 and the left guide unit GPL and theright guide unit GPR do not interfere with each other.

In addition, in the display device according to still another exemplaryembodiment of the present disclosure, the left guide unit GPL(including, e.g., GPL1, GPL2, and GPL3) and the right guide unit GPR(including, e.g., GPR1, GPR2, and GPR3) may be disposed to guide theback cover 2410 to be wound and unwound. Specifically, with the backcover 2410 in a state of being wound, the first left guide unit GPL1 andthe second left guide unit GPL2 on the first left guide unit GPL1 may bewound without overlapping each other while the inner side of the firstleft guide unit GPL1 is in contact with the outer side of the secondleft guide unit GPL2. Further, an upper surface of the first left guideunit GPL1 may be disposed to be higher than a lower surface of thesecond left guide unit GPL2 with respect to the outer circumferentialsurface of the roller 151. Therefore, the second left guide unit GPL2may be guided to be inside the first left guide unit GPL1 by a part ofthe upper end of the first left guide unit GPL1 without moving outsideof the first left guide unit GPL1. Further, an upper surface of thefirst right guide unit GPR1 may be disposed to be higher than a lowersurface of the second right guide unit GPR2, from the outercircumferential surface of the roller 151. The first right guide unitGPR1 and the second right guide unit GPR2 may be wound with the innerside of the first right guide unit GPR1 and the outside of the secondright guide unit GPR2 in contact with each other. Therefore, the secondright guide unit GPR2 may be guided to be inside the first right guideunit GPR1 by a part of the upper end of the first right guide unit GPR1without moving outside of the first right guide unit GPR1. Likewise, thesecond left guide unit GPL2 and the second right guide unit GPR2 mayguide the third left guide unit GPL3 and the third right guide unitGPR3, respectively, to be disposed between the second left guide unitGPL2 and the second right guide unit GPR2. Therefore, in the displaydevice according to still another exemplary embodiment of the presentdisclosure, as the left guide unit GPL (including, e.g., GPL1, GPL2, andGPL3) and the right guide unit GPR (including, e.g., GPR1, GPR2, andGPR3) are wound with their respective inner and outer sides in contactwith each other, it is possible to guide the back cover 2410 to be woundand unwound. Therefore, when the back cover 2410 is wound around orunwound from the roller 151, it is possible to minimize deviation of theback cover 2410 from a designed position while being wound or unwound.

FIG. 26 is a plan view of a back cover of a display device according tostill another exemplary embodiment of the present disclosure. With theexception of a back cover 2610 being different, other configurations ofthe example display unit DPi of FIG. 26 may be substantially the same asthe example display unit DPh of FIGS. 24 and 25. Thus, a redundantdescription will be omitted.

As shown in FIG. 26, a left edge and a right edge of the back cover 2610may be formed to have a stepped shape. Further, a width between a firstleft portion EL1 and a first right portion ER1 of the back cover 2610may be constant. Likewise, a width between a second left portion EL2 anda second right portion ER2 of the back cover 2610 may be constant, and awidth between a third left portion EL3 and a third right portion ER3 ofthe back cover 2610 may be constant. Therefore, a width between a firstleft guide unit GPL1 and a first right guide unit GPR1 may also beconstant, a width between a second left guide unit GPL2 and a secondright guide unit GPR2 may also be constant, and a width between a thirdleft guide unit GPL3 and a third right guide unit GPR3 may also beconstant.

A width between the first left portion EL1 and the first right portionER1 in the row direction at a lower edge of the back cover 2610 may belarger than a width between the third left portion EL3 and the thirdright portion ER3 at an upper edge of the back cover 2610. The widthbetween the first left portion EL1 and the first right portion ER1 ofthe back cover 2610 in the row direction may be the largest, and thewidth between the third left portion EL3 and the third right portion ER3of the back cover 2610 in the row direction may be the smallest. Thatis, the width between the first left portion EL1 and the first rightportion ER1 of the back cover 2610, the width between the second leftportion EL2 and the second right portion ER2 of the back cover 2610, andthe width between the third left portion EL3 and the third right portionER3 of the back cover 2610 may become smaller in this order. Further,the width between the first left guide unit GPL1 and the first rightguide unit GPR1, the width between the second left guide unit GPL2 andthe second right guide unit GPR2, and the width between the third leftguide unit GPL3 and the third right guide unit GPR3 may become smallerin this order.

Since the width between the first left guide unit GPL1 and the firstright guide unit GPR1 is larger than the width between the second leftguide unit GPL2 and the second right guide unit GPR2, the first leftguide unit GPL1 and the first right guide unit GPR1 may not interferewith the rear surface of the back cover 2610. Specifically, the firstleft guide unit GPL1 and the first right guide unit GPR1 may be firstwound around the roller 151. Next, with the first left guide unit GPL1and the first right guide unit GPR1 in a state of being wound around theroller 151, the second left guide unit GPL2 and the second right guideunit GPR2 may be wound on a lower end portion of the back cover 2610between the first left guide unit GPL1 and the first right guide unitGPR1. In this case, since the width between the first left guide unitGPL1 and the first right guide unit GPR1 is larger than the widthbetween the second left guide unit GPL2 and the second right guide unitGPR2, the second left guide unit GPL2 and the second right guide unitGPR2 may not overlap the first left guide unit GPL1 and the first rightguide unit GPR1. Further, the second left guide unit GPL2 and the secondright guide unit GPR2 may be disposed to overlap a lower end portion ofthe back cover 2610 between the first left guide unit GPL1 and the firstright guide unit GPR1. Therefore, the first left guide unit GPL1 and thefirst right guide unit GPR1 may be disposed outside the second leftguide unit GPL2 and the second right guide unit GPR2 in the centerportion of the back cover 2610 so as not to interfere with the rearsurface of the center portion of the back cover 2610.

Since the width between the second left guide unit GPL2 and the secondright guide unit GPR2 is larger than the width between the third leftguide unit GPL3 and the third right guide unit GPR3, the second leftguide unit GPL2 and the second right guide unit GPR2 may not interferewith the rear surface of the back cover 2610. Specifically, with thesecond left guide unit GPL2 and the second right guide unit GPR2 in astate of being wound around the roller 151, the third left guide unitGPL3 and the third right guide unit GPR3 may be wound on the centerportion of the back cover 2610 between the second left guide unit GPL2and the second right guide unit GPR2. In this case, since the widthbetween the second left guide unit GPL2 and the second right guide unitGPR2 is larger than the width between the third left guide unit GPL3 andthe third right guide unit GPR3, the third left guide unit GPL3 and thethird right guide unit GPR3 may not overlap the second left guide unitGPL2 and the second right guide unit GPR2. Further, the third left guideunit GPL3 and the third right guide unit GPR3 may be disposed to overlapthe center portion of the back cover 2610 between the second left guideunit GPL2 and the second right guide unit GPR2. Therefore, the secondleft guide unit GPL2 and the second right guide unit GPR2 may bedisposed outside the third left guide unit GPL3 and the third rightguide unit GPR3 in the upper end portion of the back cover 2610 so asnot to interfere with the rear surface of the upper end portion of theback cover 2610.

Also, lengths of the second left guide unit GPL2 and the second rightguide unit GPR2 in the column direction may be larger than lengths ofthe first left guide unit GPL1 and the first right guide unit GPR1,respectively. Further, lengths of the third left guide unit GPL3 and thethird right guide unit GPR3 in the column direction may be larger thanthe lengths of the second left guide unit GPL2 and the second rightguide unit GPR2, respectively.

In this case, the respective lengths in the column direction of thefirst left guide unit GPL1 and the first right guide unit GPR1, of thesecond left guide unit GPL2 and the second right guide unit GPR2, and ofthe third left guide unit GPL3 and the third right guide unit GPR3 maybe determined based on a length in the column direction of the backcover 2610 needed to wind around the roller 151 once. Specifically, themore the back cover 2610 is already wound around the roller, the largerthe length of the back cover 2610 required to wind around the roller 151once more due to the increased thickness of the wound back cover 2610and display panel 120.

For example, the respective lengths of the first left guide unit GPL1and the first right guide unit GPR1 in the column direction may be equalto the length of the back cover 2610 wound once around the roller 151.In this case, a circumference of the roller 151, determined based on aradius of the roller 151 around which the back cover 2610 is wound, maycorrespond to the respective lengths of the first left guide unit GPL1and the first right guide unit GPR1. That is, the respective lengths ofthe first left guide unit GPL1 and the first right guide unit GPR1 maybe designed based on the length of the back cover 2610 wound once aroundthe roller 151.

The respective lengths of the second left guide unit GPL2 and the secondright guide unit GPR2 may be equal to a second winding length of theback cover 2610 around the roller 151. In this case, since the lower endportion of the back cover 2610 is already wound around the roller 151,the respective lengths of the second left guide unit GPL2 and the secondright guide unit GPR2 may correspond to the circumference of the roller151 with the lower end portion of the back cover 2610 wound around theroller 151. Therefore, the respective lengths of the second left guideunit GPL2 and the second right guide unit GPR2 may be larger than therespective lengths of the first left guide unit GPL1 and the first rightguide unit GPR1. That is, the respective lengths of the second leftguide unit GPL2 and the second right guide unit GPR2 may be designedbased on the length of the back cover 2610 wound around the roller 151the second time.

The respective lengths of the third left guide unit GPL3 and the thirdright guide unit GPR3 may be equal to a third winding length of the backcover 2610 around the roller 151. Since the lower end portion and thecenter portion of the back cover 2610 are already wound around theroller 151, the respective lengths of the third left guide unit GPL3 andthe third right guide unit GPR3 correspond to the circumference of theroller 151 with the lower end portion and the center portion of the backcover 2610 wound around the roller 151. Therefore, the respectivelengths of the third left guide unit GPL3 and the third right guide unitGPR3 may be larger than the respective lengths of the second left guideunit GPL2 and the second right guide unit GPR2. That is, the respectivelengths of the third left guide unit GPL3 and the third right guide unitGPR3 may be designed based on a length of the back cover 2610 woundaround the roller 151 the third time.

In FIG. 26, the back cover 2610 is illustrated as divided into a lowerend portion, a center portion, and an upper end portion based on anexample case in which the back cover 2610 is wound three times aroundthe roller 151. However, embodiments are not limited to this particularexample, and the back cover 2610 may be divided into a larger or smallernumber of areas depending on the number of times that the back cover2610 is wound around the roller 151.

In the display device according to still another exemplary embodiment ofthe present disclosure, the left edge and the right edge of the backcover 2610 each may be formed to have a stepped shape. Therefore, theleft guide unit GPL (including, e.g., GPL1, GPL2, and GPL3) and theright guide unit GPR (including, e.g., GPR1, GPR2, and GPR3) protrudingtoward the front surface of the back cover 2610 may be wound around theroller 151 without interfering with each other. Therefore, the firstleft guide unit GPL1 and the first right guide unit GPR1 may first bewound around the roller 151, and then the second left guide unit GPL2and the second right guide unit GPR2 may be wound. Further, the widthbetween the first left guide unit GPL1 and the first right guide unitGPR1 in the row direction may be larger than the width between thesecond left guide unit GPL2 and the second right guide unit GPR2.Therefore, the first left guide unit GPL1 and the first right guide unitGPR1 may not overlap the second left guide unit GPL2 and the secondright guide unit GPR2, respectively. Next, with the second left guideunit GPL2 and the second right guide unit GPR2 in a state of beingwound, the third left guide unit GPL3 and the third right guide unitGPR3 may be wound as a third turn. Further, the width between the secondleft guide unit GPL2 and the second right guide unit GPR2 in the rowdirection may be larger than the width between the third left guide unitGPL3 and the third right guide unit GPR3. Therefore, the second leftguide unit GPL2 and the second right guide unit GPR2 may not overlap thethird left guide unit GPL3 and the third right guide unit GPR3,respectively. Accordingly, in the display device according to stillanother exemplary embodiment of the present disclosure, the back cover2610 may have a stepped shape, so that the rear surface of the backcover 2610 and the left guide unit GPL and the right guide unit GPR maynot interfere with each other.

In the display device according to still another exemplary embodiment ofthe present disclosure, the left edge and the right edge of the backcover 2610 may have a stepped shape based on the length in the columndirection of the back cover 2610 wound once around the roller 151.Therefore, the left guide unit GPL and the right guide unit GPRprotruding toward the front surface of the back cover 2610 may guide theback cover 2610 to be wound and unwound. For example, when the roller151 makes one rotation, the first left guide unit GPL1 and the firstright guide unit GPR1 of the back cover 2610 may be wound around theroller 151. When the roller 151 makes a second rotation, the second leftguide unit GPL2 and the second right guide unit GPR2 of the back cover2610 may be wound on the lower end portion of the back cover 2610between the first left guide unit GPL1 and the first right guide unitGPR1. In this case, the width between the first left guide unit GPL1 andthe first right guide unit GPR1 in the row direction may be larger thanthe width between the second left guide unit GPL2 and the second rightguide unit GPR2. Therefore, the second left guide unit GPL2 and thesecond right guide unit GPR2 may be disposed between the first leftguide unit GPL1 and the first right guide unit GPR1. When the roller 151makes a third rotation, the third left guide unit GPL3 and the thirdright guide unit GPR3 of the back cover 2610 may be wound on the centerportion of the back cover 2610 between the second left guide unit GPL2and the second right guide unit GPR2. Further, the width between thesecond left guide unit GPL2 and the second right guide unit GPR2 may belarger than the width between the third left guide unit GPL3 and thethird right guide unit GPR3. Therefore, the third left guide unit GPL3and the third right guide unit GPR3 may be disposed between the secondleft guide unit GPL2 and the second right guide unit GPR2. In this case,the first left guide unit GPL1 and the first right guide unit GPR1protrude beyond than the lower surface of the second left guide unitGPL2 and the second right guide unit GPR2 to guide the second left guideunit GPL2 and the second right guide unit GPR2 to be disposed betweenthe first left guide unit GPL1 and the first right guide unit GPR1.Similarly, the second guide unit GPL2 and the second right guide unitGPR2 protrude beyond than the lower surface of the third left guide unitGPL3 and the third right guide unit GPR3 to guide the third left guideunit GPL3 and the third right guide unit GPR3 to be disposed between thesecond left guide unit GPL2 and the second right guide unit GPR2.Therefore, in the display device according to still another exemplaryembodiment of the present disclosure, the left guide unit GPL and theright guide unit GPR protruding toward the front surface of the backcover 2610 may guide the back cover 2610 to be wound around or unwoundfrom the roller 151.

The exemplary embodiments of the present disclosure also include atleast the following:

In an example embodiment according to one aspect of the presentdisclosure, a display device may comprise: a display panel including adisplay area on which a plurality of display elements is disposed and anon-display area on which one or more wires for driving the plurality ofdisplay elements are disposed; a back cover attached to one surface ofthe display panel and having a plurality of openings; a roller unitwhich winds or unwinds the back cover and the display panel; and alifting unit which moves the back cover and the display panel in avertical direction. Further, the plurality of openings may overlap thedisplay panel, each of the plurality of openings may be disposed to bestaggered with one or more of the openings in an adjacent row, a size ofthe back cover may be larger than a size of the display panel, and eachof a plurality of edges of the back cover may correspond to a respectiveone of a plurality of edges of the display panel and may protrudeoutside of the respective one of the plurality of edges of the displaypanel.

In an example embodiment, the above display device may further comprisea housing unit which accommodates the back cover and the display panel.

In an example embodiment, the back cover may include: a first supportarea at an upper area of the back cover; a second support area fastenedwith the roller unit at a lower area of the back cover; and a malleablearea between the first support area and the second support area. Theplurality of openings may be disposed in the malleable area.

In an example embodiment, the malleable area may include; a firstmalleable area extending from the first support area toward the lowerarea of the back cover; a third malleable area extending from the secondsupport area toward the upper area of the back cover; and a secondmalleable area between the first malleable area and the third malleablearea. The back cover may further include: a third support area betweenthe first malleable area and the second malleable area; and a fourthsupport area between the second malleable area and the third malleablearea.

In an example embodiment, the above display device may further comprise:a flexible film disposed at one end of the display panel; and a printedcircuit board connected to the flexible film. The display panel may bedisposed in the third support area and the second malleable area. Theflexible film and the printed circuit board may overlap the fourthsupport area.

In an example embodiment, with the back cover and the display panelfully wound around the roller unit, the third support area may be flat.

In an example embodiment, a first fastening hole may be disposed in thefirst support area to fasten the first support area and the lifting unitwith each other, and a second fastening hole may be disposed in thesecond support area to fasten the second support area and the rollerunit with each other. Each of the first fastening hole and the secondfastening hole may have a shape different from a shape of the pluralityof openings.

In an example embodiment, the lifting unit may include a head barfastened to the first fastening hole in the first support area. With thehead bar fastened to the first fastening hole, a stress concentrated onthe first fastening hole may be relieved in the first malleable area.

In an example embodiment, the lifting unit may include a head barfastened to the first fastening hole of the first support area and bentin an inverted L shape. The first malleable area may be bent in the sameshape as the head bar.

In an example embodiment, the malleable area may include a plurality ofreinforcement areas which extends in a length direction of the pluralityof openings and is disposed to be spaced apart from each other. Theplurality of openings may be disposed in an area of the malleable areaother than the plurality of reinforcement areas.

In an example embodiment, a maximum width MW of each of the plurality ofreinforcement areas for a width direction of the plurality of openingsmay be determined by a following equation: MW−2×└√{square root over((R+t1+t2×a)²−(R+t1)²)}┘, wherein t1 is a thickness of the back cover,t2 is a thickness of an adhesive layer disposed between the back coverand the display panel, “a” is a compressibility of the adhesive layer,and R is a radius of a roller of the roller unit.

In an example embodiment, the back cover may further include a pluralityof protrusions in the plurality of reinforcement areas on a surface ofthe back cover opposite to a surface facing the display panel.

In an example embodiment, the plurality of protrusions may have at leastone of a rectangular shape, a sine wave shape, and a zigzag pattern.

In an example embodiment, a distance between an uppermost portion and alowermost portion of the plurality of protrusions may be equal to orsmaller than the maximum width of the plurality of reinforcement areas.

In an example embodiment, the malleable area may include an edgereinforcement area extending in a width direction of the plurality ofopenings and defined at an edge of the malleable area. A width of one ofthe openings in the edge reinforcement area may be smaller than a widthof one of the openings in the malleable area outside the edgereinforcement area.

In an example embodiment, the plurality of openings may have at leastone of a rectangular shape, an oval shape, a ribbon shape, a dumbbellshape, and a rhombus shape.

In an example embodiment according to another aspect of the presentdisclosure, a display device may comprise: a display panel including adisplay area on which a plurality of display elements is disposed and anon-display area on which one or more wires for driving the plurality ofdisplay elements are disposed; a back cover supporting the display paneland having a plurality of openings; a housing unit configured toaccommodate the display panel and the back cover; a roller unitconfigured to wind or unwind the display panel and the back cover in acolumn direction; and a lifting unit configured to move the displaypanel and the back cover in or out of the housing unit. Further, a widthof the plurality of openings in the column direction may be smaller thana width of the plurality of openings in a row direction, a size of theback cover may be larger than a size of the display panel, and each of aplurality of edges of the back cover may correspond to a respective oneof a plurality of edges of the display panel and may protrude outside ofthe respective one of the plurality of edges of the display panel.

In an example embodiment, boundaries of the plurality of openings mayextend in a direction different from the row direction.

In an example embodiment, boundaries of the plurality of openings mayhave a curved surface.

In an example embodiment, the back cover may include: a first supportarea at one end of the back cover fastened with the lifting unit; asecond support area at the other end of the back cover fastened with theroller unit; a first malleable area extending from the first supportarea toward the second support area; a third support area extending fromthe first malleable area toward the second support area; a secondmalleable area extending from the third support area toward the secondsupport area; a fourth support area extending from the second malleablearea toward the second support area; and a third malleable area betweenthe fourth support area and the second support area. The plurality ofopenings may be disposed in the first malleable area, the secondmalleable area, and the third malleable area.

In an example embodiment, the above display device may further comprisea flexible film and a printed circuit board which are electricallyconnected to the display panel and overlap the fourth support area. Thedisplay panel may overlap the third support area and the secondmalleable area.

In an example embodiment, with the back cover in a fully unwound state,the first support area, the first malleable area, the third supportarea, and the second malleable area may be disposed outside the housingunit, and the fourth support area, the third malleable area, and thesecond support area may be disposed in the housing unit.

In an example embodiment, the second malleable area may include aplurality of reinforcement areas extending in the row direction anddisposed to be spaced apart from each other. The plurality of openingsmay be disposed in an area of the second malleable area other than theplurality of reinforcement areas.

In an example embodiment, a width of the plurality of reinforcementareas in the column direction may be smaller than a distance between theplurality of reinforcement areas in the column direction.

In an example embodiment, the back cover may further include a pluralityof protrusions each protruding from one surface of a respective one ofthe plurality of reinforcement areas. The display panel may be disposedon an opposite surface of the one surface.

In an example embodiment, the plurality of protrusions may be configuredto be integrated with the plurality of reinforcement areas.

In an example embodiment according to yet another aspect of the presentdisclosure, a rollable display device may comprise: a flexible displaypanel including a display area on which a plurality of display elementsis disposed and a non-display area on which one or more wires fordriving the plurality of display elements are disposed; a back coverwhich is larger than the flexible display panel and is attached to onesurface of the flexible display panel; a roller unit which winds orunwinds the back cover and the flexible display panel; and a liftingunit which moves the back cover and the display panel in a verticaldirection. The back cover may include a first support area, a secondsupport area, and a malleable area disposed between the first supportarea and the second support area and having a plurality of openings. Theflexible display panel may be disposed in the malleable area. Each of aplurality of edges of the back cover may protrude outside of thenon-display area of the flexible display panel.

In an example embodiment, the back cover may further include: a secondmalleable area disposed between the first support area and the malleablearea; a third malleable area disposed between the second support areaand the malleable area; a third support area disposed between the secondmalleable area and the malleable area; and a fourth support areadisposed between the third malleable area and the malleable area. Theplurality of openings may be further disposed in the second malleablearea and the third malleable area.

In an example embodiment, the above rollable display device may furthercomprise a flexible film disposed at one end of the flexible displaypanel, and a printed circuit board connected to the flexible film. Theflexible display panel may be disposed in the third support area and themalleable area. The flexible film and the printed circuit board may bedisposed in the fourth support area.

In an example embodiment, a first fastening hole may be disposed in thefirst support area to fasten the first support area and the lifting unitwith each other.

In an example embodiment, a second fastening hole may be disposed in thesecond support area to fasten the second support area and the rollerunit with each other.

In an example embodiment, the malleable area may include a plurality ofreinforcement areas extending in a length direction of the plurality ofopenings and disposed to be spaced apart from each other. The pluralityof openings may be disposed in an area of the malleable area other thanthe plurality of reinforcement areas.

In an example embodiment, the back cover may further include a pluralityof protrusions in the plurality of reinforcement areas and on a surfaceof the back cover opposite to a surface facing the flexible displaypanel.

In an example embodiment, a width of the plurality of openings in acolumn direction may be smaller than a width of the plurality ofopenings in a row direction.

In an example embodiment, the malleable area may include an edgereinforcement area extending in a width direction of the plurality ofopenings and defined at an edge of the malleable area. A width of one ofthe openings in the edge reinforcement area may be smaller than a widthof one of the openings in the malleable area outside the edgereinforcement area.

Although the exemplary embodiments of the present disclosure aredescribed above in detail with reference to the accompanying drawings,the present disclosure is not limited thereto and may be embodied inmany different forms without departing from the technical concept of thepresent disclosure. Therefore, the exemplary embodiments of the presentdisclosure are provided for illustrative purposes only and are notintended to limit the technical concept of the present disclosure. Thescope of the technical concept of the present disclosure is not limitedthereto. Therefore, it should be understood that the above-describedexemplary embodiments are illustrative in all aspects and do not limitthe present disclosure. The protective scope of the present disclosureshould be construed based on the following appended claims, and all thetechnical concepts in the equivalent scope thereof should be construedas falling within the scope of the present disclosure.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the display device of thepresent disclosure without departing from the spirit or scope of thedisclosure. Thus, it is intended that the present disclosure cover themodifications and variations of this disclosure provided they comewithin the scope of the appended claims and their equivalents.

What is claimed is:
 1. A display device, comprising: a display panelincluding a display area on which a plurality of display elements isdisposed and a non-display area on which one or more wires for drivingthe plurality of display elements are disposed; a back cover attached toone surface of the display panel and having a plurality of openings; aroller unit which winds or unwinds the back cover and the display panel;and a lifting unit which moves the back cover and the display panel in avertical direction, wherein: the plurality of openings overlaps thedisplay panel, each of the plurality of openings is disposed to bestaggered with one or more of the openings in an adjacent row, a size ofthe back cover is larger than a size of the display panel, and each of aplurality of edges of the back cover corresponds to a respective one ofa plurality of edges of the display panel and protrudes outside of therespective one of the plurality of edges of the display panel.
 2. Thedisplay device according to claim 1, further comprising: a housing unitwhich accommodates the back cover and the display panel.
 3. The displaydevice according to claim 2, wherein the back cover includes: a firstsupport area at an upper area of the back cover; a second support areafastened with the roller unit at a lower area of the back cover; and amalleable area between the first support area and the second supportarea, wherein the plurality of openings is disposed in the malleablearea.
 4. The display device according to claim 3, wherein the malleablearea includes: a first malleable area extending from the first supportarea toward the lower area of the back cover; a third malleable areaextending from the second support area toward the upper area of the backcover; and a second malleable area between the first malleable area andthe third malleable area, and wherein the back cover further includes: athird support area between the first malleable area and the secondmalleable area; and a fourth support area between the second malleablearea and the third malleable area.
 5. The display device according toclaim 4, further comprising: a flexible film disposed at one end of thedisplay panel; and a printed circuit board connected to the flexiblefilm, wherein the display panel is disposed in the third support areaand the second malleable area, and wherein the flexible film and theprinted circuit board overlap the fourth support area.
 6. The displaydevice according to claim 5, wherein, with the back cover and thedisplay panel fully wound around the roller unit, the third support areais flat.
 7. The display device according to claim 4, wherein: a firstfastening hole is disposed in the first support area to fasten the firstsupport area and the lifting unit with each other, a second fasteninghole is disposed in the second support area to fasten the second supportarea and the roller unit with each other, and each of the firstfastening hole and the second fastening hole has a shape different froma shape of the plurality of openings.
 8. The display device according toclaim 7, wherein the lifting unit includes a head bar fastened to thefirst fastening hole in the first support area, and wherein, with thehead bar fastened to the first fastening hole, a stress concentrated onthe first fastening hole is relieved in the first malleable area.
 9. Thedisplay device according to claim 7, wherein the lifting unit includes ahead bar fastened to the first fastening hole of the first support areaand bent in an inverted L shape, and wherein the first malleable area isbent in the same shape as the head bar.
 10. The display device accordingto claim 3, wherein the malleable area includes a plurality ofreinforcement areas which extends in a length direction of the pluralityof openings and is disposed to be spaced apart from each other, andwherein the plurality of openings is disposed in an area of themalleable area other than the plurality of reinforcement areas.
 11. Thedisplay device according to claim 10, wherein a maximum width MW of eachof the plurality of reinforcement areas for a width direction of theplurality of openings is determined by a following equation:MW=2×[√{square root over ((R+t1+t2×a)−(R+t1)²)}], wherein t1 is athickness of the back cover, t2 is a thickness of an adhesive layerdisposed between the back cover and the display panel, “a” is acompressibility of the adhesive layer, and R is a radius of a roller ofthe roller unit.
 12. The display device according to claim 10, whereinthe back cover further includes a plurality of protrusions in theplurality of reinforcement areas on a surface of the back cover oppositeto a surface facing the display panel.
 13. The display device accordingto claim 12, wherein the plurality of protrusions has at least one of arectangular shape, a sine wave shape, and a zigzag pattern.
 14. Thedisplay device according to claim 13, wherein a distance between anuppermost portion and a lowermost portion of the plurality ofprotrusions is equal to or smaller than the maximum width of theplurality of reinforcement areas.
 15. The display device according toclaim 3, wherein the malleable area includes an edge reinforcement areaextending in a width direction of the plurality of openings and definedat an edge of the malleable area, and wherein a width of one of theopenings in the edge reinforcement area is smaller than a width of oneof the openings in the malleable area outside the edge reinforcementarea.
 16. The display device according to claim 1, wherein the pluralityof openings has at least one of a rectangular shape, an oval shape, aribbon shape, a dumbbell shape, and a rhombus shape.
 17. A displaydevice, comprising: a display panel including a display area on which aplurality of display elements is disposed and a non-display area onwhich one or more wires for driving the plurality of display elementsare disposed; a back cover supporting the display panel and having aplurality of openings; a housing unit configured to accommodate thedisplay panel and the back cover; a roller unit configured to wind orunwind the display panel and the back cover in a column direction; and alifting unit configured to move the display panel and the back cover inor out of the housing unit, wherein: a width of the plurality ofopenings in the column direction is smaller than a width of theplurality of openings in a row direction, a size of the back cover islarger than a size of the display panel, and each of a plurality ofedges of the back cover corresponds to a respective one of a pluralityof edges of the display panel and protrudes outside of the respectiveone of the plurality of edges of the display panel.
 18. The displaydevice according to claim 17, wherein boundaries of the plurality ofopenings extend in a direction different from the row direction.
 19. Thedisplay device according to claim 17, wherein boundaries of theplurality of openings have a curved surface.
 20. The display deviceaccording to claim 17, wherein the back cover includes: a first supportarea at one end of the back cover fastened with the lifting unit; asecond support area at the other end of the back cover fastened with theroller unit; a first malleable area extending from the first supportarea toward the second support area; a third support area extending fromthe first malleable area toward the second support area; a secondmalleable area extending from the third support area toward the secondsupport area; a fourth support area extending from the second malleablearea toward the second support area; and a third malleable area betweenthe fourth support area and the second support area, wherein theplurality of openings is disposed in the first malleable area, thesecond malleable area, and the third malleable area.
 21. The displaydevice according to claim 20, further comprising: a flexible film and aprinted circuit board which are electrically connected to the displaypanel and overlap the fourth support area, wherein the display paneloverlaps the third support area and the second malleable area.
 22. Thedisplay device according to claim 20, wherein, with the back cover in afully unwound state: the first support area, the first malleable area,the third support area, and the second malleable area are disposedoutside the housing unit, and the fourth support area, the thirdmalleable area, and the second support area are disposed in the housingunit.
 23. The display device according to claim 20, wherein the secondmalleable area includes a plurality of reinforcement areas extending inthe row direction and disposed to be spaced apart from each other, andwherein the plurality of openings is disposed in an area of the secondmalleable area other than the plurality of reinforcement areas.
 24. Thedisplay device according to claim 23, wherein a width of the pluralityof reinforcement areas in the column direction is smaller than adistance between the plurality of reinforcement areas in the columndirection.
 25. The display device according to claim 23, wherein theback cover further includes a plurality of protrusions each protrudingfrom one surface of a respective one of the plurality of reinforcementareas, and wherein the display panel is disposed on an opposite surfaceof the one surface.
 26. The display device according to claim 25,wherein the plurality of protrusions is configured to be integrated withthe plurality of reinforcement areas.
 27. A rollable display device,comprising: a flexible display panel including a display area on which aplurality of display elements is disposed and a non-display area onwhich one or more wires for driving the plurality of display elementsare disposed; a back cover which is larger than the flexible displaypanel and is attached to one surface of the flexible display panel; aroller unit which winds or unwinds the back cover and the flexibledisplay panel; and a lifting unit which moves the back cover and thedisplay panel in a vertical direction, wherein: the back cover includesa first support area, a second support area, and a malleable areadisposed between the first support area and the second support area andhaving a plurality of openings; the flexible display panel is disposedin the malleable area; and each of a plurality of edges of the backcover protrudes outside of the non-display area of the flexible displaypanel.
 28. The rollable display device according to claim 27, whereinthe back cover further includes: a second malleable area disposedbetween the first support area and the malleable area; a third malleablearea disposed between the second support area and the malleable area; athird support area disposed between the second malleable area and themalleable area; and a fourth support area disposed between the thirdmalleable area and the malleable area, wherein the plurality of openingsis further disposed in the second malleable area and the third malleablearea.
 29. The rollable display device according to claim 28, furthercomprising: a flexible film disposed at one end of the flexible displaypanel; and a printed circuit board connected to the flexible film,wherein the flexible display panel is disposed in the third support areaand the malleable area, and wherein the flexible film and the printedcircuit board are disposed in the fourth support area.
 30. The rollabledisplay device according to claim 28, wherein a first fastening hole isdisposed in the first support area to fasten the first support area andthe lifting unit with each other.
 31. The rollable display deviceaccording to claim 28, wherein a second fastening hole is disposed inthe second support area to fasten the second support area and the rollerunit with each other.
 32. The rollable display device according to claim27, wherein the malleable area includes a plurality of reinforcementareas extending in a length direction of the plurality of openings anddisposed to be spaced apart from each other, and wherein the pluralityof openings is disposed in an area of the malleable area other than theplurality of reinforcement areas.
 33. The rollable display deviceaccording to claim 32, wherein the back cover further includes aplurality of protrusions in the plurality of reinforcement areas and ona surface of the back cover opposite to a surface facing the flexibledisplay panel.
 34. The rollable display device according to claim 27,wherein a width of the plurality of openings in a column direction issmaller than a width of the plurality of openings in a row direction.35. The rollable display device according to claim 27, wherein themalleable area includes an edge reinforcement area extending in a widthdirection of the plurality of openings and defined at an edge of themalleable area, and wherein a width of one of the openings in the edgereinforcement area is smaller than a width of one of the openings in themalleable area outside the edge reinforcement area.